Unnamed: 0
int64 0
11.3k
| label
stringclasses 20
values | content
stringlengths 6
66.5k
|
|---|---|---|
7,200 |
sci.electronics
|
re what to do with old k simms jhaines eniac seas upenn edu jason haines writes i was wondering if people had any good uses for old k simms so if you have an inovative use or want to buy some simms i would be very interested in hearing about it about a month ago there was a photo posted on alt binaries pictures misc of a inch northern pike which had been caught on a lure made of k simms gordon s hlavenka cgordon vpnet chi il us vote straight ticket procrastination party dec rd
|
7,201 |
sci.electronics
|
motorola mc and mc let me try sending this message again i botched up the margins the first time sorry bout that does anyone out there know of any products using motorola s neuron r chips mc or mc if so what are they and are they utilizing standard network variable types snvt ted van den heuvel heuvel neptune iex com kx p
|
7,202 |
sci.electronics
|
re trace size for a amp supply acollins uclink berkeley edu andy collins writes how thick do i need to make a pcb trace for amps of current and does anybody have any other thoughts on the process what kind of pcb to use materials thickness of copper any advice graciously accepted in four replies i ve seen no hard numbers so here goes for traces on the outside not inner layers expect in oz copper at amps the following temperature rises versus width this is from sams reference data for engineers seventh edition pg which claims in turn to be from mil std c width temp rise inches degrees c at amps the rise for the width is only about degrees power goes as square of the current plus the copper resistance goes up as temperature goes up certainly mm traces should be ample for what you want to do and ounce copper almost cuts the required width in half i d do oz at about width myself i think given that the rated current is amps and the is a transient or fault condition there s another question will the voltage drop be low enough but you should be able to figure this one out with wire tables or just the resistivity of copper keep traces short and use separate sensing traces where appropriate as mentioned by another poster
|
7,203 |
sci.electronics
|
re looking for mhz spread spectrum modules butts shocker ee twsu edu ronald w butts jr writes i am looking for suppliers of mhz spread spectrum radio modules i need to implement a two way audio band link essentially the guts of a cordless mhz phone is what i want this isn t exactly audio but take a look in rf design magazine april for the article a robust signaling technique for part rf control netowrk applications page sources of parts are mentioned in the same issue is an article that features a chipset for the digital european cordless telecommunications standard
|
7,204 |
sci.electronics
|
re a question about vac outlet wiring crisp ecsvax uncecs edu russ crisp writes so here s my question it seems to me that i d have the same electrical circuit if i hooked a jumper from the neutral over to the ground screw on new three prong grounding outlets what s wrong with my reasoning here may i respectfully suggest you not do this the ground is supposed to be a protective ground and though what you suggest looks good on paper it s dangerous to rely on the same wire for power and protection it d never meet code and if you now own the property and later sell it you may end up with liabilities you don t want and if you don t now own it well there s a wiring faq that i think addresses this i believe an alternative is use of a gfci but i m really not sure what current code allows in this area the gfci senses alternate unwanted current paths and doesn t rely on a specific protective ground wire at least not beyond the gfci in the protected circuit gfci breakers are available but expensive
|
7,205 |
sci.electronics
|
re single chip receiver for fsk john ackermann x jra law daytonoh ncr com wrote my next project is to come up with an if detector module for fast to kb sec packet radio use no fancy modulation scheme just wide fsk for use at or mhz i m a bit familiar with the motorola chip but i wonder if there are newer designs that might work at higher input frequencies my goal is to come up with an inexpensive design for a receiver back end with if input on one end and an fsk demondulator on the other i m particularly interested in ways to use a higher if than do any current chips work up to say mhz with internal downconversion so a normal if filter can be used any suggestions john what you describe is very close to what i built and described in the th arrl computer network conference proceedings i built watt fsk transceivers at mhz they are essentially double conversion transverters with digital mod and demod at mhz the receiver uses the mc which is the same fsk receiver chip i used previouslyu in the mbps ghz data link i first published in ham radio and which is now also in the arrl handbook the mc which includes a vhf converter section could also be used at these speeds there is a newer and perhaps slightly improved design of this the mc if i remember rightly while using this would have let me reduce the external if count on receive it didn t really offer all that much help on transmit so i didn t bother with it the radios i built were first designed and built for kbps in a mhz channel but later reduced to half that these kbps radios actually have done quite well in across the bench tests at kbps and speed is pretty much a function of filter design handling the data stream is another matter entirely some of the existing radios are currently deployed on hilltops in a beacon test mode while there is not yet end end two way data flow due to lack of resources to debug software for the digital hardware mio also shown in the cnc proceedings data is perfect copy at n gn even though the data clock is currently at about half speed the a kbytes of the test text chapter of isaiah takes only a little over of a second i ve been hoping that someone would get interested enough to step in and get involved in writing code to make the whole thing usable borland ide environment with remote debugging possible as mentioned in the proceedings but to date a couple of us have been on our own and running low on resources of time money and energy if anyone in the sf bay area wants to check it out there is also a cw id after the text on the mark side at mhz from beacons on sonoma mtn and black mtn overlooking si valley the antenna is horizontally polarized i guess in retrospect my suggestions are that this is a fairly costly approach if the radios are intended for users rather than backbones and you might want to carefully consider your target if you can t arrange your paths such that you have complete line of sight i think you ll want to address the inter symbol interference caused by multipath and probably link c n budgets if paths are very far from los for more details see the th cnc i m currently working on a spread spectrum direct conversion design to address some of these problems i d be glad to help as i can with any design problems glenn elmore n gn n gn k mc amateur ip glenn santarosa ampr org internet glenne sr hp com
|
7,206 |
sci.electronics
|
tdr plug in i have an hp tdr plug in for an hp series scope or mainframe that i m never going to use no scope any more if you re interested in it please let me know price probably real cheap this notice may have appeared once before i posted and it never showed up on our local server dave medin phone w ssd networking h intergraph corp m s gd internet dtmedin catbyte b ingr com huntsville al uucp uunet ingr b catbyte dtmedin everywhere you look at least around my office the opinions expressed here are mine or those of my machine
|
7,207 |
sci.electronics
|
tv reception heelllppp hello i just canceled my support of the cable regime and i would like to at least pick up the networks and nbc i do not have tons of money nor even a few pounds so what i am looking for is the best solution for reception for under dollars i have seen modules that you plug into your wall outlet that supposedly make your entire house an antenna i have to admit even with my limited knowledge of wavelength and aerial reception this seems dubious in its claims for excellent reception at best i ll try anything though if it works i am in a non mountainous area approximately miles from the transmitting stations which are pretty large montgomery alabama pop and colombus goergia pop any recommendations of products brand names prices and company info catalog ordering numbers addresses etc thank you in advance paul sylvester shanley pshanley humsci auburn edu voice
|
7,208 |
sci.electronics
|
heavy duty antenna simulation software i would be interested in hearing from anyone who knows of good software for antenna simulation particularly in source form suitable for unix workstations though good pc software would also be of interest i m aware of the numerous mininec mutations and have been using mn for some time now i m primarily interested in hf vhf and low uhf mhz designs mostly wire antennas but for thick wires and mesh surfaces as well as for your basic thin wire assumption is anything interesting happening with nec itself i ve seen a version that was mutilated to run sort of under microsoft fortran but i m not sure how many new and improved versions of the code might be out there somewhere i d also be interested in non nec derivatives the ones i ve seen have been aimed at microwave applications but if there is something out there useful at the lower frequencies i d like to know about it thanks don rice e mail ddr flux isr alaska edu internet geophysical institute fnddr alaska bitnet university of alaska flux ddr span fairbanks ak phone loran n e
|
7,209 |
sci.electronics
|
re ic packages in article apr sol ctr columbia edu seema madvlsi columbia edu seema varma writes hi i am looking for some help in choosing a package for a high speed silicon adc mhz currently being fabricated this is a phd research project and i have to test the chip at speed on a pcb i expect to have roughly packaged circuits and will do dc low speed and high speed testing using different set ups for the test chip i know for sure that a dip will not work the long lead lines have too high an inductance getting a custom made package is too expensive so i am trying to choose between a flatpak and a leadless chip carrier the flatpack would be hard to test since it has to be soldered on to the test setup and i would spend loads of time soldering as i kept changing the test chip the leadless chip carrier sockets also have long lead lines and may not work at high speeds does anyone out there have experience knowledge of this field i would greatly appreciate help any ideas names of companies manufacturing holders sockets packages would help p s the multi layer fancy gaas packages seem like a bit of overkill seema varma you didn t mention whether or not cost is an issue where exactly are you running mhz the digital side ttl ecl we run mhz and mhz all over our ic test equipment all day long in the ecl domain and we use dip s along with plcc s mil and mil pitch pin qfp s to name a few i don t see a problem in packaging as long as you adhere to sound engineering practices a good source of information is motorola s mecl system design handbook the latest ed is dated that is considered to be one of the bibles in high speed design the very fact that you need to build a test fixture means you re most likely going to need a socket it in itself has far more inductance per pin than the package you are testing not to mention any impedance discontinuities i don t see the big concern over the packaging because it probably isn t going to make that much difference if you re trying to get ttl to run at mhz have fun ttl was never designed to run in a mhz environment aaron p s my opinions have nothing to do with my company the standard disclaimer applies
|
7,210 |
sci.electronics
|
re adcom cheap products in article apr hippo ru ac za webb itu webber ah writes stuff deleted i was also sceptical about the amps being built in the far east or where ever but if you look in the amp and see what components they use and how it was designed you can easily see why the amplifiers sound so brilliant good point also i wouldn t be surprised that the components they use off shore are of inferior quality as long as it was properly designed and robust premium components are used it shouldn t matter where it is assembled i cannot see why people say the amplifier won t last not with those quality components inside sure the amp runs very fairly hot but that s how you get an amp to sound incredibly good an amp that runs hot has no bearing on how it s gonna sound the amp you have probably is running class a the whole day actually i d be wary of excessively hot amps cauz even though the components inside may be rated to run that way excessive heat will dramatically shorten the life of any electronic component regardless of quality in fact an amp that does run hot to the touch is because either the engineer or manufacturer of that amp wanted to skimp on heatsinking or cooling to save costs hmmmmm aaron
|
7,211 |
sci.electronics
|
re what do nuclear site s cooling towers do in article c l x kj vcd hp com johne vcd hp com john eaton writes s s walker man swalker uts edu au wrote during the nuclear fission reaction the uranium fuel can get hot enough to melt when this happens the liquid uranium is pumped to the cooling tower where it is sprayed into the air nonsense first the uranium fuel is sealed in zirconium alloy cylinders which don t melt in any circumstances short of major failure of the power plant second the primary water that circulates inside the reactor core is never pumped into the cooling tower it s the secondary water cycle that goes through the cooling tower third liquid uranium would burst into flame on contact with air contact with the cool outside air will condense the mist and it will fall back to the cooling tower floor there it is collected by a cleaning crew using shop vacs and is then reformed into pellets for reactor use the next day cleaning crew working in a mist of uranium this is a toxic heavy metal even if it weren t radioactive shouldn t there be some smileys here or frowneys john whitmore
|
7,212 |
sci.electronics
|
fluke scopemeter has anybody out there used tested these new fluke scopemeters how do they compare to a low end tectronix oscilloscope are there any big drawbacks about these handheld scopes when compared to the benchtop scopes of the same price range any info on the fluke scopemeters would be greatly appreciated thanks bob freire rsf houxa att com
|
7,213 |
sci.electronics
|
re tv reception heelllppp at miles a conventional set of tv antennas on a pole one aimed at each transmitter location should work well rabbit ears inside the house are probably not adequate gadgets to plug into your house wiring are even worse at vhf you don t want a big antenna you want a resonant antenna michael a covington associate research scientist artificial intelligence programs mcovingt ai uga edu the university of georgia phone athens georgia u s a amateur radio n tmi
|
7,214 |
sci.electronics
|
optoisolator interfacing questions i am interfacing some simple circuits that run on v to my cpu board which runs at v the optoisolator is a n on the led side i put the signal i want through a k resistor to the base of a n on the transistor side i tie my cpu input line to the collector which has a pull up resistor of k it functions ok but seems very slow i can detect pulses that occur at about khz but not much faster isn t the rise fall time of this device something like us i should be able to detect my target of khz but i can t get khz this is done using wire wrap and the wires going to the cpu and to the test pin are about inches long but i m not doing anything high speed in the art of electronics it mentions tying the base of the phototransistor to ground through a resistor to improve the speed is that what i need to do how do i calculate the resistor value paul malenfant pmalenfa kitkat webo dg com
|
7,215 |
sci.electronics
|
pinout needed for til i ve recently picked up some til display chips but i can t find any information on them it seems they are no longer made by ti and i don t have an old enough data book it appears to have a dot matrix led display capable of showing one hex digit it is in a pin dip package but pins and are not present if you have any information on this part pinout power requirments functions please send me e mail thank you gary segal motorola inc segal oscar rtsg mot com cellular infrastructure division we are standing here only to gaze at the wind
|
7,216 |
sci.electronics
|
pads model of a hc has anyone done a model of the pin version of the hc it doesn t seem to be too big a job but if someone else has already done it many thanks ken martin
|
7,217 |
sci.electronics
|
re need help with car stereo in article qih ho usenet ins cwru edu ae cleveland freenet edu paul simundza writes my friend has a nice alpine car stereo and it only has channels but one of them does not work it does not put out any current or voltage at all is that channel therefore blown i then shut the radio off and ran continuity into the two speaker ouputs of the channel and it charged and discharged so i know the wires just aint bad this probably only tells you that the dc blocking capacitor that s in series between the one chip single ended audio amp and the speaker terminal is there any ideas open it up and look for the power amp ics they ll be fairly obvious replace the one connected to the dead output also how would i locate where the signal of the radio tape unit is before it gets amplified because then couldn t i hook up rca outputs to that signal so then he could just use a little amplifier well one thing you should do is poke around the terminals of the power amp chips use a probe with a m resistor like a scope probe connected to the input of a small audio amp w speaker if you find line level input to both chips one of the chips is bad and can probably replaced pretty easily if you want to pick off a near line level signal suitable for feeding to an outboard amp the outer legs of the volume control pot will often be good enough this is before the volume control and usually before the tone and balance controls too if you take off from the center and ground legs of the volume pot this will be after the volume control but again probably before the other controls if the unit is a modern type with an electronic volume control chip you should probably forget the whole thing jamie hanrahan kernel mode systems san diego ca internet jeh cmkrnl com uucp uunet cmkrnl jeh cis
|
7,218 |
sci.electronics
|
anyone know about data i o device proggers i keep finding these programmers in local junk shops this may mean that they are indeed junk but i d like to hear from anyone else that may have met up with them the basic device is a data i o a universal programmer and the usual pod is a logicpak a vo with a a programming tester adapter i d really like to hear from anyone who knows whether these monsters are worth bothering with all i want to do is blast palce v s ideas folks mike
|
7,219 |
sci.electronics
|
re history question others said early pa i recall reading of a phonograph which used mechanical amplification compressed air was squirted out of a valve which was controlled by the pickup the result was noisy and distinctly lo fi but much louder than a conventional phonograph it tended to wear the disks out pretty quickly though an now deceased prof told us willing students about a project he had worked on during wwii they needed a mega power pa with very clear audio quality the purpose was to bellow at refugees from aircraft their solution was a giant compressed air source and a horn with parallel shutters worked by a small audio system i think he said it worked very well thus the war dept cancelled the project a host is a host from coast to coast wb foz skybridge scl cwru edu no one will talk to a host that s close linux unless the host that isn t close pob is busy hung or dead
|
7,220 |
sci.electronics
|
re ic packages in article apr sol ctr columbia edu seema madvlsi columbia edu seema varma writes getting a custom made package is too expensive so i am trying to choose between a flatpak and a leadless chip carrier the flatpack would be hard to test since it has to be soldered on to the test setup and i would spend loads of time soldering as i kept changing the test chip the leadless chip carrier sockets also have long lead lines and may not work at high speeds does anyone out there have experience knowledge of this field i would greatly appreciate help any ideas names of companies manufacturing holders sockets packages would help check with kyocera america inc prime park way suite natick ma they are one of the largest manufacturers of ic packaging in the world it sounds like you would be a good candidate for wafer probing or at least ic probing to test performance hp cascade microtech and tektronix should be able to help you here one note testing at high frequency accurately can be an expensive business andrew karanicolas mit microsystems technology laboratory ankleand mtl mit edu
|
7,221 |
sci.electronics
|
re exploding tv others said why would the picture tube explode or even smoke naw it was the penguin on top of the set that exploded a host is a host from coast to coast wb foz skybridge scl cwru edu no one will talk to a host that s close linux unless the host that isn t close pob is busy hung or dead
|
7,222 |
sci.electronics
|
re how do di boxes work in article lancer apr oconnor wpi edu lancer oconnor wpi edu stephe lewis foskett writes i m doing sound for a couple of bands around here and we need direct input boxes for the keyboards these are the little boxes that take a line level out of the keyboard and transform it into low z for the run to the mixer sadly they cost like or more each and i m going to need like or of them i looked inside one belonging to another band and it looks like just a transformer does anyone have any plans for building them each don t bother trying to make one yourself just shop around a little i ve found dod brand di boxes for as cheap as each you can get higher end ones for more but for pa use for bands i wouldn t bother making one yourself might work but getting a sturdy enough enclosure might be hard they re made of heavy guage metal since they re always on the floor being kicked around a lot for any additional questions on this topic you might want to post to rec audio pro lukas zahas lzahas bu edu
|
7,223 |
sci.electronics
|
radio shack voice recognition chips hi there i have a friend who d like to get a hold of a bunch of those simple voice recognition chips that radio shack used to sell and no longer does if anybody knows of a source for these please e mail me i ll forward the responses to him thanks joel kolstad
|
7,224 |
sci.electronics
|
switch mode power supply is there a typical component or set of components that are at fault when a switch mode power supply goes south the supply is for a disk drive any general hints would be appreciated thanks mark tarbell suite com at fault when a switch mode power supply goes south the supply is for a disk drive any general hints would be appreciated thanks mark tarbell s bvh j
|
7,225 |
sci.electronics
|
re can microwaves be used to collect xyz coordinates where can you get info brochures on differential gps systems and where to buy them bobc
|
7,226 |
sci.electronics
|
re help how to construct home built battery for rd grade sci report in making batteries you could use copper and zinc in an acid electrolyte copper copper wire pennies are now mostly zinc if i recall correctly zinc zinc strip hardware stores arround here seattle sell this to prevent moss buildup on the roof an alternative would be to use a galvanized zinc coated nail electrolyte lemon juice citric acid is the active ingrediant sp volta late th century scientist used a stack for his batteries copper disk paper disk soaked in acid zinc disk copper disk paper they were advanced technology for the time gerald edgar gwe atc boeing com the opinions expressed in this communication may not reflect those of my employer
|
7,227 |
sci.electronics
|
motorola xc rc and rc i just installed a motorola xc rc fpu in an amiga a board mhz with capability to clock the fpu separately previously a mc rc was installed and everything was working perfectly now the systems displays a yellow screen indicating a exception when it check for the presence type of fpu when i reinstall an mc rc the system works fine but with the xc even at mhz it does not work the designer of the board mentioned that putting a pullup resistor on data strobe ohm might help but that didn t change anything does anybody have some suggestions what i could do does this look like a cpu fpu communications problem or is the particular chip dead it is a pull not new moreover the place i bought it from is sending me an xc rc i thought that the rc were labeled mc not xc for not finalized mask design are there any mc rc thanks christian
|
7,228 |
sci.electronics
|
telephone on hook off hok allmichael covingtontelephone on hook off hok mc from mcovingt aisun ai uga edu michael covington mc organization ai programs university of georgia athens mc aye there s the rub if you draw enough current to light an led th mc equipment at the phone company will think you ve gone off hook mc in the on hook state you re not supposed to draw current ok lets have some calculation here going by australian standards which i presume might be similar to other countries if not lets have some input a phone uses ohm to loop a v line ma a standard led drains ma so what is the actual loop current required for an off hook indication do you know cheers peter t
|
7,229 |
sci.electronics
|
what s a good ic for rs alltall cool onewhat s a good ic for rs tc from rky uxa cso uiuc edu tall cool one tc organization university of illinois at urbana tc i m looking for an ic that will convert rs voltage levels to ttl vo tc levels something relatively inexpensive would be nice too anyone tc a suggestion thanks try a maxim max cpe pin dil converts v to v for commms what a clever little gizmo peter t
|
7,230 |
sci.electronics
|
swr meter for cb radios allthe devil reincarnateswr meter for cb radios td from ssave ole cdac com the devil reincarnate td organization cdac wa td what td is a good choice for a cb or wave td i read the installation instructions on a wave antenna td and they suggested that i use an swr to tune it at channel td and channel for a minimum reading question is why channel td and the best antenna is one that will let out the most wave probably not the best explanation but the rest makes sense a one wave will cancell itself out btw no such beastie the best is a wave antenna followed by then etc as for swring in what you actually do is trim the antenna to the correct length for the specific wavelength you will be transmitting on since the wavelength varies with the channel you use then it s recommended to swr in using the middle channel of those you are going to use anyway in the beginning of cb s all new antennas had to be swr ed in nowdays manufactures trim the antennas almost spot on so that there s not much point in swring then again you may be a fanatic and whish to do it anyway cheers peter t
|
7,231 |
sci.electronics
|
what s exactly in a flour allmartin mccormickwhat s exactly in a flour mm from martin datacomm ucc okstate edu martin mccormick mm organization oklahoma state university stillwater ok mm what sort of lamp is the little glass bulb found inside the starter mm it sort of reminds me of a ne neon lamp starters appear open when m mm with an ohm meter so the little lamp is either a neon or has a capacit mm in series with it mm mm i have seen these things all my life but never read a really good mm description of what is happening inside that little can do you know what a bi metallic strip is just in case it is two strips of different metals bonded together which when heated bend to one side check out the blinker globe in your christmas tree lights so when you turn on the power this causes the bulb to work like a neon heating up and shorting out thus providing a loop to power the heaters in the main tube when the tube fires insufficient current runs through the starter to keep the heat up and the bi metalic strip straightens out o c btw i too thought that they were nothing more than a small neon so one day when the neon in my sisters digital flip the metal squares type clock broke flimsy leads i replaced it with one from a starter well powering up made a bit of a mess of the clock cheers peter t
|
7,232 |
sci.electronics
|
dmm advice needed allmartin emdedmm advice needed me from mce bcstec ca boeing com martin emde me organization boeing me me i an currely in the market for a dmm and recently saw an add me for a kelvin does anyone own one of these or some me other brand that they are extremely happy with how do the me small name brands compare with the fluke and beckman brands me i am willing to spend for one me me any help is greatly appreciated please email me me martin if you are going to use one where it counts eg aviation space scuttle etc then i suggest you go and buy a fluke never seen a beckman however for every other use you can buy a cheapie i have a metex which is some made up name as i have seen the same dmm with other brand names on it i bought it about yrs ago for aus convert that to us and you see that it s definetly a cheapie so far it has proved to be accurate taken moderate abuse and has many features on it cap freq transistor check etc i am very happy with it and would definetly not buy a fluke just for the name hope this helps cheers peter t
|
7,233 |
sci.electronics
|
re what do nuclear site s cooling towers do in article qlg o d q sequoia ccsd uts edu au swalker uts edu au s s walker man wrote i really don t know where to post this question so i figured that this board would be most appropriate i was wondering about those massive concrete cylinders that are ever present at nuclear poer sites they look like cylinders that have been pinched in the middle does anybody know what the actual purpose of those things are i hear that they re called cooling towers but what the heck do they cool except for their size the cooling towers on nuclear power plants are vertually identical in construction and operation to cooling towers designed and built in the s a hundred years ago for coal fired power plants used for lighting and early electric railways basicly the cylindrical tower supports a rapid air draft when its air is heated by hot water and or steam circulating thru a network of pipes that fill about the lower of the tower to assist cooling and the draft water misters are added that spray cold water over the hot pipes the cold water evaporates removing the heat faster than just air flow from the draft would and the resulting water vapor is rapidly carried away by the draft this produces the clouds frequently seen rising out of these towers that slight pinch maybe of the way up the tower is there because it produces a very significant increase in the strength and rate of the air draft produced compared to a straight cylinder shape the towers are used to recondense the steam in the sealed steam system of the power plant so that it can be recirculated back to the boiler and used again the wider the temperature difference across the turbines used in the power plant the more effecient they are and by recondensing the steam in the cooling towers before sending it back to the boilers you maintain a very wide temperature difference sometimes as high as degrees or more from first stage hot turbine to final stage cold turbine r tim coslet usenet r tim coslet cup portal com technology n domesticated natural phenomena
|
7,234 |
sci.electronics
|
re telephone on hook off hok in article aa insane apana org au peter m insane apana org au peter tryndoch writes mc aye there s the rub if you draw enough current to light an led th mc equipment at the phone company will think you ve gone off hook mc in the on hook state you re not supposed to draw current ok lets have some calculation here going by australian standards which i presume might be similar to other countries if not lets have some input a phone uses ohm to loop a v line ma a standard led drains ma so what is the actual loop current required for an off hook indication do you know up to microamperes on hook over something like ma off hook in between defective line and the phone company comes looking for leaky insulation michael a covington associate research scientist artificial intelligence programs mcovingt ai uga edu the university of georgia phone athens georgia u s a amateur radio n tmi
|
7,235 |
sci.electronics
|
re rams roms with ale latches for s intel also makes some neat memory and peripheral chips old technology early s ram plus io slow ram as i recall eprom plus io expensive and slow intel does make eproms with built in address latches i fear that you would need a very flexible and up to date eprom programmer to write to them give them a call i am not able to locate their memory products book yet sigh now who borrowed it robert
|
7,236 |
sci.electronics
|
re history question in article qnroe d n usenet ins cwru edu wb foz skybridge scl cwru edu david lesher writes an now deceased prof told us willing students about a project he had worked on during wwii they needed a mega power pa with very clear audio quality the purpose was to bellow at refugees from aircraft their solution was a giant compressed air source and a horn with parallel shutters worked by a small audio system i think he said it worked very well thus the war dept cancelled the project gee i got the idea from somewhere that devices like this were in common use in wwii so that commanders on board ships could bellow at the troops landing on a beach for example which reminds me of an anecdote from the mid s at a communications conference a marine corps communications officer said he didn t care much for all the spread spectrum multi access expensive communication systems that people were talking about at the time what he wanted was a kilowatt broadcast transmitter on the ship and a japanese transistor radio stuck in the ear of every marine hitting the beach haynes cats ucsc edu haynes cats bitnet ya can talk all ya wanna but it s dif rent than it was no it aint but ya gotta know the territory meredith willson the music man
|
7,237 |
sci.electronics
|
re history question in article snap paj uk co gec mrc paul johnson writes this is vague so i am posting it in case anyone else knows more i recall reading of a phonograph which used mechanical amplification compressed air was squirted out of a valve which was controlled by the pickup the result was noisy and distinctly lo fi but much louder nasa and related agencies apparently used this same principles to create the loudest reported reproduced sound they used an analog electrically controlled valve to control the flow of air across a horn throat if i remember correctly it was called a modulated air blast transducer there were reports of the thing being able to produce db hz mile distance communicate directly with fighter pilots ft etc regards gordon waters clyde gordon bme georgia institute of technology atlanta ga out of the mountain of despair we can hew the stone of hope mlk jr uucp decvax hplabs ncar purdue rutgers gatech prism gt a internet gt a prism gatech edu
|
7,238 |
sci.electronics
|
re subliminal message flashing on tv hi i was doing research on subliminal suggestion for a psychology paper and i read that one researcher flashed hidden messages on the tv screen at ths of a second is that possible i thought the maximum rate the tv was even capable of displaying images was th of a second or th of a second for an image composed of only odd or even scan lines you are correct the fastest complete image that could be presented on tv would be one field which is of a second approximately of course the phrase tv screen is often thrown around in reference to any crt display so perhaps this researcher wasn t using normal tv rates might even be a vector strokewriter display in which case the lower limit on image time is anyone s guess and is probably phosphor persistence limited bob myers kc ew hewlett packard co opinions expressed here are not systems technology div those of my employer or any other myers fc hp com fort collins colorado sentient life form on this planet
|
7,239 |
sci.electronics
|
re scope questions if my life depended on it i d say that it s a scope that uses long persistance phosphor to keep the successive taces on the screen for some unit of time store them do i get to live we ll let you live but just this once there s more to a real storage scope than just a long persistence phosphor actually the phosphor isn t usually anything special at all what makes a storage tube work is a screen placed just behind the phosphor which becomes charged as the electron beam intially writes the trace with the trace now written to the screen a separate low level flood electron gun keeps the image lit by exciting those areas of phosphor which are next to the written areas on the storage screen there are some problems with this the resolution is limited compared to a non storage tube and the stored trace tends to bloom with time of course this is pretty much obsolete technology done in by the current digital scopes which use raster scan displays and keep everything in a frame buffer memory anyways filip i ll buy a vowel gieszczykiewicz best e mail fmgst pitt edu ah yes from the same people who brought you that amazing new reading program that s sweeping eastern europe hooked on consonants bob myers kc ew hewlett packard co opinions expressed here are not systems technology div those of my employer or any other myers fc hp com fort collins colorado sentient life form on this planet
|
7,240 |
sci.electronics
|
re dmm advice needed in article aa insane apana org au peter m insane apana org au peter tryndoch writes if you are going to use one where it counts eg aviation space scuttle etc then i suggest you go and buy a fluke never seen a beckman however for every other use you can buy a cheapie my beckman died a few days ago thanks do about a or foot drop onto a lab table probably not indicative of anything but i ve already filled out the requisition for a fluke oh yeah and sometimes our measurements here do count not often but often enough that i want at least one good meter joel kolstad
|
7,241 |
sci.electronics
|
re what do nuclear site s cooling towers do excerpts from netnews sci electronics apr re what do nuclear site s by r tim coslet cup portal from r tim coslet cup portal com subject re what do nuclear site s cooling towers do date fri apr pdt in article qlg o d q sequoia ccsd uts edu au swalker uts edu au s s walker man wrote i really don t know where to post this question so i figured that this board would be most appropriate i was wondering about those massive concrete cylinders that are ever present at nuclear poer sites they look like cylinders that have been pinched in the middle does anybody know what the actual purpose of those things are i hear that they re called cooling towers but what the heck do they cool except for their size the cooling towers on nuclear power plants are vertually identical in construction and operation to cooling towers designed and built in the s a hundred years ago for coal fired power plants used for lighting and early electric railways basicly the cylindrical tower supports a rapid air draft when its air is heated by hot water and or steam circulating thru a network of pipes that fill about the lower of the tower to assist cooling and the draft water misters are added that spray cold water over the hot pipes the cold water evaporates removing the heat faster than just air flow from the draft would and the resulting water vapor is rapidly carried away by the draft this produces the clouds frequently seen rising out of these towers that slight pinch maybe of the way up the tower is there because it produces a very significant increase in the strength and rate of the air draft produced compared to a straight cylinder shape the towers are used to recondense the steam in the sealed steam system of the power plant so that it can be recirculated back to the boiler and used again the wider the temperature difference across the turbines used in the power plant the more effecient they are and by recondensing the steam in the cooling towers before sending it back to the boilers you maintain a very wide temperature difference sometimes as high as degrees or more from first stage hot turbine to final stage cold turbine r tim coslet usenet r tim coslet cup portal com technology n domesticated natural phenomena great explaination however you left off one detail why do you always see them at nuclear plants but not always at fossil fuel plants at nuclear plants it is prefered to run the water closed cycle whereas fossil fuel plants can in some cases get away with dumping the hot water as i recall the water isn t as hot thermodynamically in many fossil fuel plants and of course there is less danger of radioactive contamination wayne martin
|
7,242 |
sci.electronics
|
re electronic odometers was used bmw question in article c hhko ry vu vlsi ee vill edu mobasser vu vlsi ee vill edu bijan mobasseri writes there are two simple procedures for alterating any odometer mechanical driven odometer remove the speedo cable from the transmission attach a drill and run at max speed until the speedo turns over continue until the desired mileage is reached admittedly an irrelavent question for how long should the drill be running bijan a verrrrrry long time like on the order of days i had the pleasure of doing that once playing with the speedo cable and with my b d heavy duty at full speed rpm all the speedo ever got up to was mph now if you go a high speed drill and ran it at say rpm you could get mph out of it if you speedo doesn t burn out anyways to roll a mile odometer would take days or so much easier just to take the speedo apart thought i d share btw all this info was obtained legally o computer lesson one there is no any key alternate keys are shift ctrl caps lock alt and sometimes tab mvanmeet ub d umn edu consultant at lab
|
7,243 |
sci.electronics
|
grounding power wiring was re a question about vac outlet wiring there has been quite a bit of discussion about house wiring and grounding practices here a few points need to be clarified the equipment grounding conductor green green with a yellow stripe bare or the metal sheath or pipe of some wiring methods is used as a safety ground to carry fault currents back to the circuit breaker panel and to limit the voltage on the metal case of utilization equipment or other metal objects it should never except for a few exceptions to be discussed later carry the normal operating current of a connected load some equipment has filters in the power supply which may cause some slight current flow through the grounding conductor much communications or audio equipment is sensitive to noise or slight voltages on the grounding conductor and may require special wiring of the grounding conductors to provide reliable operation orange outlets are often used for this with insulated grounding conductors wired back to the panel box and in many cases back to the service anyone installing such a system should read both the section on grounding in the national electric code and publications on installing quiet isolated ground systems the code requires the insulated grounding conductors green wires to run with the current carrying conductors back to the panel box and if required back all the way to the service entrance where it is bonded to the service ground water pipe or rod many of these systems are installed illegally or unsafely where they do not provide a safe ground or a quiet ground or either the grounded conductor of a circuit often called the neutral which is referred to in the code as the identified conductor and is supposed to be white or natural grey this conductor is supposed to be connected to ground in most electrical systems at a single point generally at the service entrance panel this connection is through the main bonding jumper in many household service panels the main bonding jumper is actually a bonding screw which attaches the neutral busbar to the case of the panel the grounded conductor neutral is generally a current carrying conductor in the case of a volt circuit it is one of the two conductors completing the circuit from the panel to the load device since the grounded conductor neutral is only connected to the grounding conductor bare or green at the service entrance if the load is any distance from the service and draws any significant current there will be a small but measurable voltage between the grounded and grounding conductors at the load under normal operating conditions if you should incorrectly connect the grounded neutral conductor to the grounding conductor at the load some of the neutral current will flow instead through the grounding conductor since there will now be current flowing through the grounding conductor it will also no longer be quite at ground potential at the load end if the load equipment has a metal case which is connected to the grounding conductor through the u ground plug the metal case is now also no longer quite at ground potential the difference under normal non short circuit conditions may be only a few tenths of a volt but it could also be a volt or two this normally does not present a shock hazard however if you let the metal case of the grounded equipment come into contact with an independently grounded object such as a water or gas pipe a radiator a metal air conditioning duct or such part of the neutral current will try to flow through this aalternate ground path if the contact is not solid you will get a significant arc a low voltage but possibly moderate current arc under the wrong conditions this arcing could start a fire it is possible in some cases that the sneak ground current could also flow through a wire of inadequate size causing it to overheat with the incorrect non single point grounding of the neutral if there is a short circuit from hot to neutral the high short circuit current which may flow will cause a much higher voltage on the grounding conductor which increases the possibility for shock or fire also if you incorrectly multiply connect the neutral and ground the voltage on the ground system is seen as noise bu computer or audio equipment often causing malfunction i have spent some hours tracking down such shorts in technical facilities where they were inducing severe hum into equipment the neutral is usually bonded to the ground at the distribution transformer as well as at the service entrance of each dwelling this is done primarily for lightning protection so that induced lightning currents have a short path back to ground and also to assure that the currents drawn by shorts to grounded objects like pipes draw enough current to trip circuit breakers or blow fuses quickly the bad side of this is that not all the neutral current from the dwelling goes through the neutral wire back to the transformer some of it flows through the grounding electrode water pipe etc this may cause corrosion in the pipes and possibly in things like underground fuel oil tanks and it may also cause measurable ac magnetic fields due to the large loop between the hot conductors in the service and the neutral current in the water pipe and ground there are those who feel these fields may be unhealthy don t flame me on this i m just telling you where the field comes from not it s health effect as far as i m concerned the jury is still out on this note that the bonding jumper is only installed at the main panel not at any sub distribution panels this is one reason why it is illegal to run service entrance cable with the sheath used as a neutral to a sub panel you must have a seperate insulated conductor for the neutral the sheath can be used in this application only as the grounding conductor if the neutral is bonded to the grounding conductor in the sub panel say by forgetting to remove the bonding screw all the grounding conductors of the loads on that panel will be above ground with the possible problems listed above the code makes exceptions for ranges and dryers as well as feeds from one building to another in the cases of the range and dryer the neutral may be used as the equipment ground under certain conditions instead of a seperate wire every time the code is revised these exceptions come up for review these exceptions were in fact the first required safety grounds in the days before u ground outlets and such the appliance manufacturers don t want to have to redesign their ranges and driers and the contractors don t want to have to run four wire cable with four fairly heavy expensive wires in place of three wire to the appliances no question it would be safer with seperate neutrals to the stove but the neutral current is low for most burner settings since most current is in the volt hots except at some low settings the wires are large gauge and there are few reported cases of injury or damage so far the exceptions have survived in the case of feeds between buildings it s primarily for lightning protection people doing wiring should be aware what is and what isn t a legal grounding conductor obviously the bare wire in romex with ground is anywhere there is a green wire installed such as in a portable cord that is a good grounding conductor the sheath of bx clamped in bx connectors in metal boxes is a legal grounding conductor in the us bx has an aluminum band run under the steel sheath to lower the resistance of the sheath you can just cut this aluminum band off at the ends you don t have to bond it to anything it does its job by touching every turn of the bx sheath conduit or emt thinwall tubing is generally a legal grounding conductor but may require a bonding locknut where it enters a box or panel particularly for larger pipes greenfield looks like big bx but you pull your own wires in the empty sheath after you run it is not a legal grounding conductor as it doesn t have the aluminum band to bond it and the spiral steel has too much resistance and inductance you have to run a seperate green grounding conductor inside the greenfield wiremold is also not a legal grounding conductor as the paint on the boxes often prevents good contact and the feed to the wiremold extension is often from a box in the wall that may not be well connected to the first wiremold box i have personally discovered cases where the entire run of wiremold and the cases of everything plugged into all the outlets on the run were hot with volts why do i get a shock every time i touch my computer and the radiator here in the office because there was no ground wire in the wiremold and one of the outlets had shorted to the edge of the wiremold box you must run a ground wire back in the wiremold from the outlets at least to the first box in the original wiring conduit bx etc where you can bond the wire to the box with a screw bnding clip or whatever on another issue while you should ground the green wire lug on gcfi outlets when ever there is a place to ground them it is legal in the nec to use them without a ground if no ground is available it is better to have the protection of the ground fault interrupter than no protection if you don t install it the interrupter doesn t depend on the ground to trip it is desirable to connect the ground if available because if the ground is connected the interrupter will trip as soon as a faulty device is plugged in whereas without the ground it will not trip until someone or something provides a ground path for those questioning the legal use of ungrounded gcfi s read in the nec d exception this is the code my code is in the city but i know the rule hasn t changed it might be renumbered though we have only touched the surface concerning grounding there is much more to this subject but most of you have fallen asleep by now john john h schmidt p e internet schmidt auvax adelphi edu technical director wbau phone days adelphi university evenings garden city new york fax
|
7,244 |
sci.electronics
|
re what to do with old k simms in article ql ug i sunb ocs mq edu au johnh macadam mpce mq edu au john haddy writes in article netnews upenn edu jhaines eniac seas upenn edu jason haines writes i was wondering if people had any good uses for old k simms i have a bunch of them for the apple mac and i know lots of other people do to i have tried to sell them but have gotten no interest so if you have an inovative use or want to buy some simms i would be very interested in hearing about it the most practical use i ve seen for them is as key ring ornaments johnh i used a bunch as weights when building a model airplane hung them on the stringers across the stringer or whatever worked pretty well kelly
|
7,245 |
sci.electronics
|
re can i use a cd analog multiplexer for digital signal as the subject says can i use a for digital signals i don t see why it couldn t handle digital signals but i could be wrong anyone have any advice thanks yes i use hc and others commerically for this purpose so rest assured it works fine in one case i route bit serial digital audio using these and it is difficult to see any signal degradation at all which surprised me given some pretty fast edges hc is spec d at something like db mhz into ohms the more complex types are generally a little slower and more resistive plain series are not so good at handling v logic remember that the output load is seen by the input device tc e mail tchannon black demon co uk or tchannon cix compulink co uk
|
7,246 |
sci.electronics
|
re whats wrong with my cordlessphone i ve also found that the electronic starters on these instant on compact fluourescent lamp fixtures kick out interference that nukes my cordless phone i can hear it in my guitar amplifier too paul marxhausen university of nebraska lincoln grace happens
|
7,247 |
sci.electronics
|
uart cpu rom ram subsystem this is a followup post to something i ve written previously several people responded with good information but i don t think i communicated exactly what i am looking for i m working on a custom i o device that will communicate with a host via rs my custom circuitry will use an c eb or ec cpu and require about k of ram preferably flash ram in looking around i see that lots of people have engineered uart cpu rom ram subsystems that are ready to be interfaced to your custom i o devices it s been done so much that it would be best if i can avoid reinventing a system it just needs to use an c or cpu and be able to load a program from the host then transfer control to that program well there s one other thing the rom needs to know how to do it should have routines to send and receive bytes to from the host that utilize the hardware control lines dtr rts dts cts everything i ve seen is in the and up range that s too much for this application i need something around the cpu has the uart built in so you re only looking at a few chips does anyone know a company that markets a good board in this range or some public domain circuitry i can use thanks in advance for the info rich
|
7,248 |
sci.electronics
|
re chip chipset for code barcode llbgb utxdp dp utexas edu wrote distribution usa reply to lihan ccwf cc utexas edu while i m on the net bugging everyone is there such a thing as a chip or chipset to decode code barcode i ask for a couple of reasons mainly i want a reasonably compact encoding scheme to write information on magstripe cards and code appears to be about right if the right way to do it is something else and it s reasonably easy can someone let me know i might not get a chance to reply too quickly to this or my earlier post but i ll get to them within a couple days i think thanx everyone bgb lihan ccwf cc utexas edu hewlett packard has a series of barcode decoder ics hbcr hbcr and hbcr and they support of extended of interleaved of and upc codes the and pieces add codabar and code these chips support hp s barcode wands and slot readers an a heds wand run about cdn ian
|
7,249 |
sci.electronics
|
oscilliscopes for sale recently i posted two oscilliscopes for sale one has sold the other is still available used good condition hitachi v mhz dual channel portable analog oscilliscope o mv div o dc offset o alternate magnification x magnified non magnified waveform o vert mode trigger o tv sync separation circuit list price and the price fry s electronics just quoted sells for jdr microdevices current price products international your price used obo i haven t gotten an offer at the asking price so obo applies i also have a broken version of the scope which sold jdr mhz dual channel portable analog oscilliscope o mv div o component tester resistors caps diodes coils o tv video sync filter o z axis input intensity modulation broken means the crt produces a nice bright trace but the trace does not correspond to the input signal my guess is it s repairable but more than a simple calibration problem but i honestly have not tried to calibrate the scope or otherwise fix it it s as is i paid for it in its current state i bought it thinking i d repair it using the good scope for side by side comparison since i ve sold the good scope the bad one doesn t do me much good and i d like to recoup that amount as above i ll accept offers and take the best one i d prefer a local bay area california buyer so a i don t have to ship it and b she or he can examine the scope prior to purchase rbn apple com
|
7,250 |
sci.electronics
|
re what do nuclear site s cooling towers do wayne alan martin wm h andrew cmu edu writes excerpts from netnews sci electronics apr re what do nuclear site s by r tim coslet cup portal from r tim coslet cup portal com subject re what do nuclear site s cooling towers do date fri apr pdt in article qlg o d q sequoia ccsd uts edu au swalker uts edu au s s walker man wrote i really don t know where to post this question so i figured that this board would be most appropriate i was wondering about those massive concrete cylinders that are ever present at nuclear poer sites they look like cylinders that have been pinched in the middle does anybody know what the actual purpose of those things are i hear that they re called cooling towers but what the heck do they cool great explaination however you left off one detail why do you always see them at nuclear plants but not always at fossil fuel plants at nuclear plants it is prefered to run the water closed cycle whereas fossil fuel plants can in some cases get away with dumping the hot water as i recall the water isn t as hot thermodynamically in many fossil fuel plants and of course there is less danger of radioactive contamination actually fossil fuel plants run hotter than the usual boiling water reactor nuclear plants there s a gripe in the industry that nuclear power uses vintage steam technology so it s more important in nuclear plants to get the cold end of the system as cold as possible hence big cooling towers oil and gas fired steam plants also have condensers but they usually are sized to get the steam back into hot water not most of the way down to ambient some plants do cool the condensers with water rather than air as one canadian official asked about thermal pollution de icing a river said up here we view heat as a resource everybody runs closed cycle boilers the water used is purified of solids which otherwise crud up the boiler plumbing when the water boils purifying water for boiler use is a bigger job than cooling it so the boiler water is recycled john nagle
|
7,251 |
sci.electronics
|
how much would a tektronix a oscilloscope fetch hi i d like to know how much the foll equipment will fetch in the used equipment market without manuals or other accessories tektronix scope tektronix a scope tektronix logic analyser thanks much for your help
|
7,252 |
sci.electronics
|
re what to do with old k simms i was wondering if people had any good uses for old k simms i have a bunch of them for the apple mac and i know lots of other people do to i have tried to sell them but have gotten no interest how hard would it be to somehow interface them to some of the popular motorola microcontrollers i am a novice at microcontrollers but i am starting to get into them for some of my projects i have several k simms laying around from upgraded macs and if i could use them as free memory in one or two of my projects that would be great one project that comes to mind is a caller id device that would require quite a bit of ram to store several hundered cid records etc dan daniel joseph rubin rubin cis ohio state edu go bengals go bucks
|
7,253 |
sci.electronics
|
getting rid of screen wiggles my monitor display has a bad case of the wigglies i have a good ground i live in an old house and i have replaced much of the wiring i have two emi filters on the computer the monitor plugs into the computer when fluorescent lights are on upstairs the display jiggles when motors run in the house the display jiggles when incandescent lights are on in the kitchen the display jiggles i could bring a separate line from the breaker box and use it only for the computer would this do it emi doesn t only travel the volt line though should i shield the back of the monitor ground a grid or plate your expertise is appreciated thanks very much ed byrnes ed byrnes fax eabyrnes vela acs oakland edu kensington academy oakland university rochester mi north america
|
7,254 |
sci.electronics
|
fluke for sale was dmm advice needed i have a spare fluke a this is a true rms digital meter with digit display it s in average condition been used but works fine which is what fluke s are all about btw according to the fellow who designed these meters they can be converted to a function by clipping a jumper and adding the extra switches like i said seems fair these sell for new alan l peterman hm work al qiclab scn rain com it s odd how as i get older the days are longer but the years are shorter
|
7,255 |
sci.electronics
|
microcontroller i would like to experiment with the intel family does anyone out there know of any good ftp sites that might have compiliers assemblers etc
|
7,256 |
sci.electronics
|
fujitsu hdd i have a fujitsu m k which has been removed i believe from a digital x ray machine takes x ray pictures without film the fujitsu part number is b b b a i have obtained some data on the device it is inch winchester type of megabyte capacity though i was told it was over megabytes however there is very little information on the interface standard used it appears to use two balanced line connections but what each connection corresponds to i know not one connection is a way idc the other a way idc if anyone has any information on this device i would be most grateful if you could provide it thanks chris powell the man from janet cjp uk ac aber internet cjp aber ac uk nyx cpowell nyx cs du edu
|
7,257 |
sci.electronics
|
re radio shack battery of the month club donrm sr hp com don montgomery writes radio shack has canceled their battery of the month club does anyone know why they say they ll honor existing cards in customer hands but no new cards will be issued i was told that this is an environmental based move i was also told that there will be somthing else to replace the battery club like maybe the k floppy club we ll see bill quinn billq ms uky edu
|
7,258 |
sci.electronics
|
re what to do with old k simms rubin cis ohio state edu daniel j rubin writes how hard would it be to somehow interface them to some of the popular motorola microcontrollers not hard you can do the refreshing and access cycles by software but this hogs most of the available cpu cycles on a low end controller i ve seen some application note from philips that used one of their derivatives as a printer buffer with up to mb of dynamic ram that was accessed and refreshed with software bit banging another alternative would be to use one of those nice dram controller chips that create static ram appearance and all that but they may be too expensive to make it worthwhile segmented memory helps structure software
|
7,259 |
sci.electronics
|
re public domain circuits in commercial applications in article apr wuecl wustl edu dp cec wustl edu david prutchi writes can circuits found in electronics magazines with no patent disclaimer be used legally as subcircuits of a commercial unit there are two issues here copyright and patent the magazine article s contents are copyrighted and may not be reproduced translated etc without the copyright holder s permission however this does not cover the ideas expressed only the form of expression copying their circuit diagram or pc board pattern is copyright infringement but it s unlikely that they could stretch copyright far enough to claim that the circuit design itself is copyrighted so long as you draw your own diagrams and lay out your own boards copyright shouldn t be an issue patents are different the author does not have to give you any warning that the design is covered by patent although it would be sensible for him to do so in fact it s possible that he was infringing on someone else s patent without realizing it ignorance of the patented status is not a defence against infringement although it might reduce the damages a court would award however unless there was something seriously novel about the circuit almost certainly it is obvious to one skilled in the art and therefore unpatentable routine engineering is not patentable patents in theory cover only inventions ideas that are genuinely new caution i am not a lawyer consulting a professional would be wise if significant amounts of money are at stake all work is one man s work henry spencer u of toronto zoology kipling henry zoo toronto edu utzoo henry
|
7,260 |
sci.electronics
|
re public domain circuits in commercial applications in article c ge lif athena cs uga edu mcovingt aisun ai uga edu michael covington writes patent law says you can build anything you want to for your own personal noncommercial use i m not up on the details of us patent law but i think this is incorrect there is a reasonable use exemption for copyright there is none for patents the exemptions from patent licensing are quite narrow r d work is exempt but personal use is not that is it s okay to experiment with a patented idea but not to put it to practical use e g to improve your stereo even if it s only your own private practical use of course it is unlikely that discreet personal use will ever be detected or that you will ever be sued over it all work is one man s work henry spencer u of toronto zoology kipling henry zoo toronto edu utzoo henry
|
7,261 |
sci.electronics
|
cad program for electronics i am making a search for a cad program that does a decent job of making schematic drawings the program needs to be in ms dos windows if possible what i want the cad program to do is to draw diagrams by dragging elements onto the screen and in this the elements needed are as diverse as vacuum tubes to ics case with pins it also needs to have provision for adding legends to the components as well as their values in other words i want to produce quality drawings printout would be to either pin dot matrix and or laser printer if you know of such a cad program that is of reasonable cost please respond fred w culpepper old dominion university retired fculpepp norfolk vak ed edu
|
7,262 |
sci.electronics
|
re sc sa specs could some kind soul post me the max power voltage current ratings of sc and sa transistors their conductance types and pinouts they are used in the sweep portion of a tv set sc maximum ratings vcbo v vceo v ic a pc w t c icbo max ua vcb v cob pf at q point vce ic a hfe sa maximum ratings vcbo v vceo v ic a pc w t c icbo max ua vcb v cob pf at q point vce v ic a hfe that s all i can get from my data book hope that helps suwanto iastate edu
|
7,263 |
sci.electronics
|
re what to do with old k simms rubin cis ohio state edu daniel j rubin writes how hard would it be to somehow interface them to some of the popular motorola microcontrollers i am a novice at microcontrollers but i am starting to get into them for some of my projects i have several k simms laying around from upgraded macs and if i could use them as free memory in one or two of my projects that would be great one project that comes to mind is a caller id device that would require quite a bit of ram to store several hundered cid records etc assuming hc in expanded muxed mode you could do it much easier if you get a dram controller ic the mmi could be used to implement this or you could use a counter and a huge multiplexer to provide row column refresh address multiplexing the thing with drams is that they require wierd timing address multiplexing and refresh actually if you wanted to use a ic you could look at an which has a neat controller built in there is also the xx i think one of those has the dram controller built in this one is for the dram however the has only one more address line adding only another component or so the k simms are basically or dram chips or their equivalent in fewer packages it can be done just takes a bit of logic design i m actually about to do it using a c p chip i ve got k simms that s megabytes on my apple e used to be in my
|
7,264 |
sci.electronics
|
re what do nuclear site s cooling towers do lots of pretty good stuff about how the huge towers near most nuclear power plants are there to cool the used steam back into near ambient temperature water deleted water as i recall the water isn t as hot thermodynamically in many fossil fuel plants and of course there is less danger of radioactive contamination actually fossil fuel plants run hotter than the usual boiling water reactor nuclear plants there s a gripe in the industry that nuclear power uses vintage steam technology so it s more important in nuclear plants to get the cold end of the system as cold as possible hence big cooling towers as a point of info some of the early nuclear power plants in this country used the fission pile as a first stage to get the water hot and then had a second stage fossil fuel step to get the water actually steam very hot i remember seeing this at con edison s indian point power plant which is about miles north of nyc and built more or less dannyb panix com all the usual disclaimers apply whatever they may be
|
7,265 |
sci.electronics
|
how starters work really in article aa insane apana org au peter m insane apana org au peter tryndoch writes so when you turn on the power this causes the bulb to work like a neon heating up and shorting out thus providing a loop to power the heaters in the main tube when the tube fires insufficient current runs through the starter to keep the heat up and the bi metalic strip straightens out o c imprecise this description ignores the role of the ballast misrepresents the heating effects in the starter the bimetalic strip cools down immediately after the contacts short circuit because the neon discharge stops and much less heat is generated from the i r loss in the metal as compared to the neon discharge the starter contacts open before the tube fires actually the tube fires as a result of the back emf generated in the ballast because of this immediate opening of the starter s contacts a capacitor is connected in parallel with the contacts to prevent excessive arcing during the firing the neon reionizes but does not draw sufficient current to prevent firing of the tube itself mustafa kocaturk mustafa seas smu edu ee dept room a caruth bldg home office smu box dallas tx
|
7,266 |
sci.electronics
|
re act in article qhrq innlri crcnis unl edu mpaul unl edu marxhausen paul writes ok what s a quick rundown on all the series variations we re repairing something with a act on it and the question arises well do i really need the act part flipping through digi key i see als as c hc ac acq act hct acht hctls here s something i posted about this a few years ago it s not fully up to date with all the new variations some of which are just different manufacturer s synonyms in practical terms ignoring the technological details this is my view of the families nb i am not a giant corporation which influences my views on things like availability and backward compatibility the original speed good power consumption fair effectively obsolete now use ls or later except for a very few oddball functions like which are hard to find in newer families h modification of for higher speed at the cost of higher power consumption very obsolete use f l modification of for lower power at the cost of lower speed very obsolete use cmos s later modification of for even higher speed at some cost in power consumption effectively obsolete use f ls combination of l and s for speed comparable to with lower power consumption best all round ttl now widest variety of devices f fast as blazes power not too bad the clear choice for high speed in ttl availability and prices generally good as failed competitor to f although a few as parts do things that are hard to find in f and thus are still useful als possible replacement for ls generally souped up still fairly new availability and prices possibly a problem c fairly old family cmos devices with ttl pinouts competed with series not too successfully obsolete use or newer cmos families thrown in as the major non non ecl logic family the old cmos family still viable because of very wide range of devices low power consumption and wide range of supply voltages not fast very forgiving and easy to work with beware static electricity but that comment applies to many other modern logic families too there are neat devices in this family that exist in no other the clear choice when speed is not important hc a new attempt at pinout cmos fast compared to old cmos power consumption often lower than ttl possibly a good choice for general purpose logic assuming availability and affordability cmos logic levels not ttl ones beware very limited range of supply voltages compared to older cmos also major rise of power consumption at faster speeds hct hc with ttl logic levels much the same comments as hc read the fine print on things like power consumption ttl compatibility in cmos involves some compromises k thrown in for speed freaks the low end of ecl various sources claim that it is easier to work with than super fast ttl for serious high speed work less forgiving though read and follow the rules or it won t work availability to hobbyists limited can be expensive k for real speed freaks hot ecl harder to handle than k and inconvenient packages much more useful datasheets however as for compatibility between families the families except c and hc are all more or less logic level compatible but how many x devices you can drive from one y output varies enormously with x and y you just have to read the specs and do the arithmetic c and hc are compatible with the others with a bit of hassle compatibility can be a bit of hassle or a lot of hassle depending on what supply voltage is using k or k to anything else is considerable hassle me i use and ls with a sprinkling of f hc t and k are interesting but i haven t used either significantly yet all work is one man s work henry spencer u of toronto zoology kipling henry zoo toronto edu utzoo henry
|
7,267 |
sci.electronics
|
re what do nuclear site s cooling towers do swalker uts edu au s s walker man writes i was wondering about those massive concrete cylinders that are ever present at nuclear poer sites they look like cylinders that have been pinched in the middle does anybody know what the actual purpose of those things are i hear that they re called cooling towers but what the heck do they cool i hope someone can help the actual hourglass is hollow and is designed to generate a draft exploiting the venturi effect around the base of the hourglass is a ring of water towers warm river water coming from the steam condenser in the plant is sprayed over louvres the draft being pulled through the tower cools the water by both evaporation and convection the sensible heat extracted from the cooling water is the driving force for draft generation it should be noted that the hourglass shaped cooling towers are used on both fossile and nuclear plants it should also be noted that at locations where water is plentiful the cooling towers are only used part time when the discharge temperature would exceed some release limit it was once thought that the warm discharge water was damaging to fish fishermen know that is thoroughly incorrect nontheless stringent usually state regulations remain in some instances since it typically takes hp worth of pumping to move the volume of water needed to cool a mwe plant the cost of using the towers is not insignificant john de armond wd oqc interested in high performance mobility performance engineering magazine tm interested in high tech and computers marietta ga send ur snail mail address to jgd dixie com perform dixie com for a free sample mag lee harvey oswald where are ya when we need ya
|
7,268 |
sci.electronics
|
re making copy of a video tape hooperw spot colorado edu wayne hooper writes victor inqmind bison mb ca victor laking writes you are experiencing what is called macrovision it is the protection that they use on the video tapes there are two ways around this that i know of first of all you can try using a different vcr to copy onto it is the input of the vcr that reacts to the protection so sometimes just switching the two vcrs around will take care of it some models just don t react to it does this also affect the viewing of tapes i have had problems with a couple of rented tapes they were virtually unviewable i fiddled with the tuning tracking and vertical hold but it was no good it sounds like your tv is one of the ones that also reacts to the video protection poor you the macroscrubber from radio electronics removes the protection so you souldn t have any more problems however if you use the method of copying it from one vcr to another where the second vcr doesn t react to the protection you will end up with a duplicate tape including the protection one thought comes to mind about your problem when playing the tape for viewing are you feeding the signal from the source vcr through an extra device before going to the tv if you feed it through a second vcr first that is your problem as to other devices such as converters i don t know if they would react or not just to be safe you might want to make sure that you have nothing between the vcr and tv victor inqmind bison mb ca the inquiring mind bbs winnipeg manitoba
|
7,269 |
sci.electronics
|
crt driver transistors device lt ic ma v br ceo v ccb pf v br cbo v vce v ic ma max polarity npn hfe min package hfe max material metal ft ghz price device lt ic ma v br ceo v ccb pf v br cbo v vce v ic ma max polarity pnp hfe min package hfe max material metal ft ghz price vce v anyone know of a source for these parts other than straight from motorolla i need lt s and lt i ve tried standard and they said we are out stephen cyberman toz buffalo ny us mangled on fri at if there s one thing i can t stand it s intolerance blue wave qwk v
|
7,270 |
sci.electronics
|
re analog switches balan michael fulbright said analog switches balanced to all on mf i am trying to build a synchronous demodulator and i ve hit a snag mf in my application i want to be able to change the gain of an mf op amp amplifier from to controlable via a digital input mf the most obvious way i ve come up with is to use analog switches mf to adjust the gain of the op amp the only analog switch i have mf experience with it the unfortunately i want to switch an mf ac signal which goes from about v to v and the is only mf for positive signals how about using a it has a seperate ground for the analog outputs it would get you bits mf another part which caught my eye was the analog devices ad this mf is a balanced demodulator which appears to fill exactly the need i mf have the data sheet was somewhat skimpy on application notes could mf someone comment on using this chip for the following application or how about a multiplying d a convertor this is essentiallty what you are makeing stephen cyberman toz buffalo ny us mangled on fri at catch the blue wave blue wave qwk v
|
7,271 |
sci.electronics
|
need diode model for pspice im designing a circuit with just a silicon diode i dont need to modify any of the parameters but the problem will not accept the following statement model diode d the pspice book i have is terrible i would appreciate any help neil gandler gandler electronics home automation electronic design technology
|
7,272 |
sci.electronics
|
wire amperage table needed does anyone has a table about the size of the wire to the amount of current it can carry probably in the amp range my friend is interested in converting a mazda into an electric car needed information for estimation thanks in advance p s any info on electric will be greatly appreaciated
|
7,273 |
sci.electronics
|
re making copy of a video tape in article hpcuhe cup hp com pi hpcuhe cup hp com paul ilgenfritz writes i think the go video dual cassette machines do a direct tape to tape copy which transfers macrovision to the copy i you can find one of these it would be worth a try go video machines used in hq mode will copy even the macrovision go video phone number ask for sales department since the state of arizona does not go on daylight savings time we effectively are in pacific time zone allen sullivan designing various stuff for go video
|
7,274 |
sci.electronics
|
re what do nuclear site s cooling towers do others said actually fossil fuel plants run hotter than the usual boiling water reactor nuclear plants there s a gripe in the industry that nuclear power uses vintage steam technology so it s more important in nuclear plants to get the cold end of the system as cold as possible hence big cooling towers when the utility gave up on that cinnci oh plant zimmer and announced they were going to convert it to a coal fired scheme the turbines were already in place and they were the low temp type so the plan was install a second set of high temp turbines and feed the low temp ones with the output of the new ones never saw anything more on this did they ever really build it a host is a host from coast to coast wb foz skybridge scl cwru edu no one will talk to a host that s close linux unless the host that isn t close pob is busy hung or dead
|
7,275 |
sci.electronics
|
re act others said s later modification of for even higher speed at some cost in power consumption effectively obsolete use f ls combination of l and s for speed comparable to with lower power consumption best all round ttl now widest variety of devices f fast as blazes power not too bad the clear choice for high speed in ttl availability and prices generally good i hate to disagree w a fellow as smart as henry but a few years back i worked on a project using lots of high speed stuff my part was slow parallel whew the mild mannered designer working on the fast serial stuff cussed swore at f all the time it was the harry reams of ttl one ultra tiny power line glitch one hickup one eyeblink across the board and bang the f had toggled counted whatevered at times he swore it would count even without any volt supply you can guess what the f stood for they would do anything to push s or work around it to avoid using f i don t think i d consider using f to replace s unless the consequences were fully understood a host is a host from coast to coast wb foz skybridge scl cwru edu no one will talk to a host that s close linux unless the host that isn t close pob is busy hung or dead
|
7,276 |
sci.electronics
|
help apple ii expansion chassis by mountain computer i recently bought an apparantly complete expansion chassis by mountain computer inc it consists of a box with apple compatible slots powersupply brick interface card and ribbon cable to attach it to the computer to be expanded there was also included a small card with empty sockets on top and pins on the bottom that looks like it would plug into the motherboard somewhere after pulling a chip there s an empty socket also on the interface card and a short pin dip jumper like the ones used with language cards this technological marvel came with no docs and i haven t a clue as how to hook this thing up if anyone has docs and or users disk of any sort for this i could really use copies of them or at least some help i need to know o how to orient the ribbon cable between the card and the chassis o how to attach the short cable from the motherboard to the card and if the small card is used o the purposes of the various jumper pins on the card it has more of those than my cms scsi card thanks john daniels ah cleveland freenet edu
|
7,277 |
sci.electronics
|
a and compatibility does any one know if the is timing pin compatible with the it seems the has in iheirent bug with cts rts handshaking and i need a suitable pin replacement to put in my serial card possibly a buffered version perhaps jolt gnu ai mit edu its not impossible just improbable johnp pro angmar uucp zaphod beeblbrox bl cleveland freenet edu n nig amsat org being a ham is so grand
|
7,278 |
sci.electronics
|
help ma current loop to rs converter needed where can i buy or build a device that will convert ma current loop signals to rs voltages i know some old terminals came with that option but none of the ones i own have that anyway i want to connect a computer to this old industrial computer to use the computer with communications software as a console instead of an old decwriter please e mail me if you have any info that would point me in the right direction
|
7,279 |
sci.electronics
|
re what do nuclear site s cooling towers do in c l x kj vcd hp com john eaton writes during the nuclear fission reaction the uranium fuel can get hot enough to melt when this happens the liquid uranium is pumped to the cooling tower where it is sprayed into the air contact with the cool outside air will condense the mist and it will fall back to the cooling tower floor there it is collected by a cleaning crew using shop vacs and is then reformed into pellets for reactor use the next day cooling towers are a lot taller than they really need to be power companies are forced to make them that tall by some enviromental law that requires the raw uranium emisions to be held to under this law is now under attack by lawyers arguing that the should be measured at the edge of the property rather than the edge of the cooling tower eliminating this law will save power companies thousands of dollars in concrete costs for new nukes john eaton hp vcd johne i think you posted your article days too late april st is over i don t like nuclear powerplants but i think it s not fair to tell such storys about them ok let me try to explain what that tower is used to st even the modernst nuclear powerplant is only a simple steam engine it has an hightech boiler but the rest is still verry verry conventional and if you ve already visited any condensation powerstation you l have seen the cooling towers too if you look at any good book about thermophysics you ll find a chapter about the carnot process which describes how to get energy from a temperature difference and that is the reason for cooling towers too you only can get energy if you ve an temperature gradient that means that you have steam on the one side and need to cool down the steam till you get water again on the other side if you want to get aprox of the energy you or better the uranium brought into the water to let it boil if you only have hot steam on the one and cold steam on the other side you ll loose much more of the energy and so they cool down the steam to get at least the of energy that carnot will give them the cooling towers are for cooling the steam the vapor you ll see is not the steam of the main core circulation because that steam is radioactive the circulation is divided in at least circuits connected about heat exchangers to prevent radioactive pollution of the environment nd ok the main core is hot but even in the modernst hightemperature reactors htr they only run at deg celsius this is still verry far away from uraniums melting point which is somewhere around deg celsius but you ll have lot s of problems with the boiler s steel that s because at this temperature the metal is attacked by steam and will corrode verry fast this is only for bwr s the new he cooled reactors have temperatures up to deg celsius but this is only experimental rd i personaly think that nuclear waste should be as low as ever possible because the dose you get will accumulate about the years today mrem and next year mrem won t be mrem at all it accumulates and even in years you ll still have mrem and i m not interested in glowing in the night and getting children with heads this is my point of view only my christian reisel student of electronic sciences christian reisel goldammerweg w buebingen germany voice fax email
|
7,280 |
sci.electronics
|
help how to reduce the rpms of a boxer fan i need to reduce the speed of a boxer fan by about i recall reading somewhere that the right capacitor in series will do it if this isn t a case of brain fade can someone suggest the cap value the specifics it s a real boxer fan tm the label says v amps al dykes adykes jpr com
|
7,281 |
sci.electronics
|
a d board quiry on an a d board i ve got i m using the a d lines it measures the voltages properly ie with a v power supply it reg s v and with v it reg s v problem is when i ve got the input voltage and i wish to lower it via a resistor the sensitivity of the board is so great that i can triger it with holding the v wire in one hand and touch the probe and it will register the full input voltage a m resistor only lowers voltage by v so this is not too feesable what could the problems be and what else could i use to lower the input voltage btw i ve got it grounded correctly inspiration comes to o baden sys bison mb ca those who baden inqmind bison mb ca seek the baden de bari unknown
|
7,282 |
sci.electronics
|
need to find out number to a phone line greetings situation i have a phone jack mounted on a wall i don t know the number of the line and i don t want to call up the operator to place a trace on it question is there a certain device out there that i can use to find out the number to the line thanks for any response al
|
7,283 |
sci.electronics
|
re what s a good ic for rs ttl signals in c zsc fl news cso uiuc edu rky uxa cso uiuc edu tall cool one writes i m looking for an ic that will convert rs voltage levels to ttl voltage levels something relatively inexpensive would be nice too anyone have a suggestion thanks well it looks as if digi key sells a chip with the number icl that does what you want they are selling it for about hope this helps frank customer asked what s that thing i answered chuckling well it s a highly technical sensitive instrument i use in computer repair being a layman you probably cann t grasp exactly what it does i call it a b f h frank w holden ka uww the radio doctor snailmail inter net addison st frankh scraps pittsburgh sgi com washington pa packet ka uww n idi wpa pa usa na disclaimer disclaimer h i confess you did it customer asked what s that thing i answered chuckling well it s a highly technical sensitive
|
7,284 |
sci.electronics
|
re need to find out number to a phone line alee ecs umass edu writes greetings situation i have a phone jack mounted on a wall i don t know the number of the line and i don t want to call up the operator to place a trace on it question is there a certain device out there that i can use to find out the number to the line thanks for any response al there usually is a way however often telephone companies like to keep all of their internal numbers private depends on your exchange any modern electronic switching equipment usually have voice synth lines that echo the number you called from the line service guys use this to make sure they connect up the right pairs of lines
|
7,285 |
sci.electronics
|
re rams roms with ale latches for s spp zabriskie berkeley edu steve pope writes in article qg sinnokf sheoak ucnv edu au jeff redgum ucnv edu au j pethybridge writes hello again i asked this a year ago but i am still looking i am getting sick of having to use a hc jeff just use the damned sure there are oddball latched memory chips but do you really want to use them sorry if i m pedantic but design your circuit using reasonably available parts and move on to more important problems we re looking at a series of chips by wsi the psd xx series they have mega address decoding logic on them various rom sizes upto mbit various ram sizes upto k and i o ports which can be chip select lines i o or the buffered address lines cute chip pin plcc package second sourcing may be a problem though bryan ryan vk tkx melbourne australia bryan philips oz au
|
7,286 |
sci.electronics
|
re what to do with old jason haines said what to do with old k to all on jh i was wondering if people had any good uses for old jh k simms i have a bunch of them for the apple mac jh and i know lots of other people do to i have tried to jh sell them but have gotten no interest how about collecting them all together ie everyones and selling them as a lot the other thing is to give to a recycler jh so if you have an inovative use or want to buy jh some simms i would be very interested in hearing jh about it if they are free and you can send them real cheap i would be intrested in them hehehe are these chip or chip devices what speed jh i have seen ram disc storage devices but they have been jh very pricey plus i am still a little worried about having data jh stored on ram why do you use a ram disk stephen cyberman toz buffalo ny us mangled on fri at badgers we don t need no steenking badgers blue wave qwk v
|
7,287 |
sci.electronics
|
re what to do with old kris gleason said re what to do with old to all on kg yeah keychains i have seen k simms with a silver kg keyring attached big seller at the computer store i m kg sure you could find a bunch of geeks h h h h h h computer kg science majors around that would buy them for maybe kg if you re lucky untrue they would check jdr first and say that s how much they are worth at most my guess is they are worth buck a peice stephen cyberman toz buffalo ny us mangled on sat at this tagline is a duplicate this tagline is a duplicate blue wave qwk v
|
7,288 |
sci.electronics
|
how does differential mode gps work i understand that the new gps boxes now have an option known as differential ready apparently land based beacons tranmit gps correction information to your gps receiver with differential option installed how does this system work what frequency is used for the land based beacons thanks in advance charlie thompson
|
7,289 |
sci.electronics
|
re need to find out number to a phone line in texas well corpus christi anyway if you pick up the phone and dial the phone company will read back the number to you try it it might work
|
7,290 |
sci.electronics
|
re need to find out number to a phone line in article bd dea ecs umass edu alee ecs umass edu writes greetings situation i have a phone jack mounted on a wall i don t know the number of the line and i don t want to call up the operator to place a trace on it question is there a certain device out there that i can use to find out the number to the line thanks for any response al how about calling someone with the caller id service and have them call you back with the number richard cook e mail rcook gfx engga uwo ca elect eng fax
|
7,291 |
sci.electronics
|
re can i use a cd analog multiplexer for digital signals tall cool one rky uxa cso uiuc edu wrote as the subject says can i use a for digital signals i don t see why it couldn t handle digital signals but i could be wrong anyone have any advice thanks the switches have a non negligable on resistance up to k ohm when powered by volts and a maximum current and a maximum static voltage across switch not a good bet for ttl should work for cmos but slow things down a bit there are hc versions that have better specs but lower max voltage mark zenier markz ssc wa com markz ssc com
|
7,292 |
sci.electronics
|
re illusion chris best cab col hp com wrote this is not a new idea at least years ago i got this little gadget with a keyboard on the back and led s in a vertical row on the front it has a long handle and when you wave it in the air it writes the message you typed on the keyboard in the air this is not news in fact it s where i got the idea from since it was such a neat item mattell made it i believe modeled after a space saber or light sword or something likewise theme y my addition was using a motor for continuous display and polar effects in addition to character graphics i should have protected it when i had the chance no one to kick but myself ten years ago is about right since i built mine in or it s even older than that i remember seeing a description of a garage operation selling them at some of the early computer faires in san francisco about years before that mark zenier markz ssc wa com markz ssc com
|
7,293 |
sci.electronics
|
voltage regulator spec needed hi there i have a mac with a burned out part which looks like a voltage regulator the part number is bu and i believe the vender is sgs thomas judging by teh sgs logo printed on the package if anyone has teh spec for this part i would greatly appreciate an email with the import info so i can find a replacement thanx in advance dave dnewman lynx northeastern edu btw i don t need people telling me to throw the computer away if i had the money the thing would be in the trash in a second but it does make a good terminal if nothing else
|
7,294 |
sci.electronics
|
re what do nuclear site s cooling towers do the object of a cooling tower is to distribute dissolved salts in cooling water over large areas of farmland and to therefore decrease farm subsidies for non producers by rendering their land infertile a side effect of this deficit reduction program is that they provide a low t reservoir for a variety of industrial processes now you know john berryhill
|
7,295 |
sci.electronics
|
re exploding tv just as a not of possible interest on this subject it is my understanding that exploding televisions were a major cause of domestic accidents in the soviet union in past years
|
7,296 |
sci.electronics
|
re a question about vac outlet wiring in article qmisf odp sdl warren mentorg com garyg warren mentorg com gary gendel writes in article cmkrnl com jeh cmkrnl com writes what you can do if you want three prong outlets without additional wiring is to use a gfci outlet or breaker but the outlet will be cheaper in fact depending on where you are putting your new outlet s a gfci may be required you still need to supply a proper ground for a ground fault circuit interrupter not according to the nec nor the cec as explained in the electrical wiring faq which i posted here separately note the material under the headings subject how do i convert two prong receptacles to three prong and subject are you sure about gfcis and ungrounded outlets should the test button work of course as they said local codes may vary so rewiring is still a part of this job however the ground may be connected to a local earth ground rather than back at the breaker box i m not sure about this if the ground connections on the outlets are connected to anything they should be connected to a wire that runs back to the main panel where it is bonded to the neutral connector and to the house ground rod a connection to a local earth ground would not necessarily meet one of the goals of the ground wire which is that if a short develops from hot to the ground wire enough current would flow to trip the breaker hmmm how are those orange isolated ground outlets often used in computer rooms wired jamie hanrahan kernel mode systems san diego ca internet jeh cmkrnl com uucp uunet cmkrnl jeh cis
|
7,297 |
sci.electronics
|
re motorola xc rc and rc in article apr rosie uh edu st my rosie uh edu stich christian e writes i just installed a motorola xc rc fpu in an amiga a board mhz with capability to clock the fpu separately previously a mc rc was installed and everything was working perfectly now the systems displays a yellow screen indicating a exception when it check for the presence type of fpu when i reinstall an mc rc the system works fine but with the xc even at mhz it does not work the designer of the board mentioned that putting a pullup resistor on data strobe ohm might help but that didn t change anything does anybody have some suggestions what i could do does this look like a cpu fpu communications problem or is the particular chip dead it is a pull not new moreover the place i bought it from is sending me an xc rc i thought that the rc were labeled mc not xc for not finalized mask design are there any mc rc i too have a xc rc math coprocessor which i installed succesfully in my mega midget racer clocked at mhz i have tried clocking my fpu at to mhz and it all worked just fine i have a mc cpu i don t know why my fpu has an xc my original mhz fpu was label mc but it seems to work fine on my system maybe you just have a bad chip stefan p s or does it mean experimental chip instead of motorola chip
|
7,298 |
sci.electronics
|
characterization of opamps hi right now i should do some characterization of opamps because i don t have special equipment for this task i have to do this job with relativly simple equipments frequency sweeper dso etc does anyone know good test circuitry for characterization of opamps especially for measuring open loop gain phase margin pssr cmmr and so on are there any books or application notes on this subject available please reply vi e mail or nn thanks mark mark niederberger e mail mniederb itr ch
|
7,299 |
sci.electronics
|
looking for electronics dept info in austrailia hi netters i am looking for the list of universities in austrailia which has electronics department i am considering to spend a year for research in austrailia about communication area i am interested in mobile communication areas and spread spectrum communications etc but i don t have any information about austrailian universities can anybody recommend a good university in co mmunic ation area any comments will be welcomed bye jaehyung kim
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.