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  1. audioguru2

    ABOUT VEROBOAD

    Hi Loveguru, I never built an Electronic Stethoscope. I just fixed the original defective project and called it version 2. I did test a biased electret microphone with a shielded cable to an LM386 that had its gain boosted with a capacitor, and heard my heart (and the TV in the next room and my...
  2. audioguru2

    stun glove

    That is what your picture looks like it's doing. We aren't making megavolts, so the sparks will be fairly small and won't jump very far.
  3. audioguru2

    in search of a FM STEREO transmitter

    Search Google for FM stereo transmitter. On page 6 there is a free link to the whole Silicon Chip project. The IC is surface-mount!Here's the schematic:
  4. audioguru2

    in search of a FM STEREO transmitter

    Sorry about Silicon Chip asking for money to see their project. I don't know how but I got in through Google for free and read the whole thing! I should have copied it 'cause now other forums are also asking about it. :-[ What was Zaire called when I went to school? Belgian Congo? Zambia was...
  5. audioguru2

    in search of a FM STEREO transmitter

    Hi Guys, I found what I think is the "South African" stereo FM transmitter kit on Google. Their description and spec's of this product is detailed (many pages) and good. I'm curious that I can't find their address anywhere on their website, but they mention shipping by US-postal service. Their...
  6. audioguru2

    in search of a FM STEREO transmitter

    Hi Alun, Channel separation in a stereo transmitter refers to the maximum dB difference between the left and right audio channels. The necessary filters reduce the separation so a left channel sound would also be heard on the right and usually sounds very distorted on the wrong channel, reduced...
  7. audioguru2

    stun glove

    Hi Alun, The spark won't shock anybody and it won't go anywhere. It will just jump from one terminal to its other terminal. If you want to shock someone, first you must connect them to one of the terminals then a spark will jump to them when they get close to the other terminal or just touch...
  8. audioguru2

    stun glove

    Hi Steven, That's right, I forgot. You are discharging the high voltage of the disposable camera's flash circuit's capacitor into a car's 12V ignition coil so the voltage gets stepped-up much higher. Maybe Glen can do that too, but use a small transformer from another flash circuit instead of an...
  9. audioguru2

    in search of a FM STEREO transmitter

    Hi Ras, I am sorry that I am not an expert on stereo FM transmitters to help you choose. I just read their spec's and reviews. (And rap or rhyme about them!) ;D Since you don't know the very basic spec's of stereo FM radios or transmitters and are not a master, maybe you should just run some...
  10. audioguru2

    stun glove

    The high-voltage capacitor in a disposable camera's flash circuit doesn't make the high voltage, it just stores it for a few seconds. Making it bigger or using more than one will just take a longer time to charge and you will end up with the same voltage. To make a higher voltage you need a...
  11. audioguru2

    in search of a FM STEREO transmitter

    Hi Ras, A search in Google for FM Transmitter showed hundreds of good inexpensive stereo FM transmitter kits, including a few that plug into a PC's PCI slot. Their frequency and power are programmed with the computer to cover your house or your whole community. I couldn't find the South African...
  12. audioguru2

    in search of a FM STEREO transmitter

    Hi Ras, Yes, FM stereo transmitters are complicated. :o If you want the transmitter to drift all over the place and sound lousy, spend only a few bucks for a few parts. If you want quality, build the $60.00US kit that is probably the least expensive quality FM stereo transmitter available. The...
  13. audioguru2

    in search of a FM STEREO transmitter

    Here's a good discussion about the NJM2035 and has a link to an excellent article, titled "Stereo for Dummies"! http://members.tripod.com/~transmitters/njm2035_1.htm
  14. audioguru2

    in search of a FM STEREO transmitter

    Hi Guys, The simple NJM2035 stereo encoder circuit is missing very important filters in its audio inputs that keep high frequency audio from beating with its 19KHz stereo pilot tone. The pre-emphasis amplifies the problem where the beats end up as interfering audio noises and messes-up the...
  15. audioguru2

    X'tors and their symmetry

    Hi Shekhar, Transistors are not symmetrical to make them have lots of gain. At a low supply voltage, a transistor will work with its emitter and collector reversed, but the gain will not be much more than one. Look at the maximum voltage ratings of a transistor. Its collector to base voltage is...
  16. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    Hi Robert, 24V at 3.25A is 78W which is a lot of heat. Maybe the solenoid is supposed to be powered by 24V only for a moment. I could probably also overheat the momentary solenoid that opens the trunk of my car if I applied power to it continuously! It uses so much current the lights dim. Can...
  17. audioguru2

    wireless transmitter

    Hi Tasmania Kid, You saw it on your 'scope. That crude and simple transmitter transmits AM as well as FM. It also transmits the 2nd harmonic of 100MHz (200MHz) and 3rd harmonic (300MHz), etc. Maybe the majority of its power is in its harmonics. So you can't simply determine its output power at...
  18. audioguru2

    How to tell if an old electrolytic cap is good

    Hi Ante, That's the one! Newer and larger Philips caps are fine. I salvaged some tiny electrolytics from Japanese equipment and they are extremely high quality. I also like their little 1/10W resistors.
  19. audioguru2

    How to tell if an old electrolytic cap is good

    My 'scope is about 40 years old and still works every day with its original electrolytic caps, but I replaced its electrically-leaky foil and paper caps years ago with good metalized poly ones. My old TV is nearly 40 and also still works but its biggest electrolytic caps are dripping. I worked...
  20. audioguru2

    Electronic Stethoscope 2

    Hi Loveguru, 1) I'm glad you got a TL072 which has two low-noise, low-distortion and wideband opamps inside, instead of the TL071 which has only one low-noise, low-distortion and wideband opamp inside. They cost about the same and also about the same or less than a noisy, distorted and...
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