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  1. audioguru2

    DC Panel meter read errors on charger

    Most electronic meters need a power supply that is completely separate from what they are measuring. A digital multimeter has its own battery, doesn't it?
  2. audioguru2

    Electronic Fuel injection enhancer

    Reading about air-fuel mixtures on the web, I read an article by a guy who ran his engine lean and burned off the edges of the pistons that hold the piston rings. From then on, he runs it slightly rich. Good luck.
  3. audioguru2

    22 W Audio Amplifier

    Each of your two 8 ohm speakers will have a max power of only 5W at clipping and will produce a max sound pressure of 93dB at 1m from a speaker. The max average sound pressure from music will be only 83dB at 1m which isn't very loud. 
  4. audioguru2

    Low-pass Filter?

    From the collector of one output transistor to +12V is a 24V square-wave. Depending on the meter, it will measure 24VAC or 8.4VAC. Which schematic did you use? The original one has errors.
  5. audioguru2

    Need some info for substitute parts

    The 1N5818 is a 1A Schottky diode with a very low forward voltage drop and it switches extremely quickly. The 1N914 is an ordinary 75mA diode with a pretty high forward voltage drop and it switches much quicker than a 1N4002 rectifier but is still much slower than a Schottky diode. When you...
  6. audioguru2

    Electronic Fuel injection enhancer

    The circuit will make the mixture leaner: 1) Less power. Less efficiency so more fuel will be used than before. 2) Much hotter combustion which results in more nitrogen oxide and melted pistons. 3) Are you also going to inject water into your engine?
  7. audioguru2

    fm

    The tap on the coil is at a lower impedance than at the end. Then a higher capacitance from your hand or metal object will have the same effect on detuning as a lower capacitance at the end which is a very high impedance.
  8. audioguru2

    Transistor Question

  9. audioguru2

    Transistor Question

    No you didn't. No it isn't. The collector-base is almost always reversed-biased in circuits and has a high breakdown voltage. For a 2N3904 it is 60V. The emitter-base is not usually reverse-biased in circuits and has a max rating of only 6V for a 2N3904. Hee, hee. ;D No, just most of the time! ;D
  10. audioguru2

    fm

    Yes. On FM transmitters that have the oscillator's collector connected to the antenna, your hands or anything metal that gets near the antenna changes the frequency of the oscillator. If you connect the antenna to a tap on the coil then the output power is less and there is less affect on the...
  11. audioguru2

    Audioguru FM Tx

    My circuit has a low power and might be blocked by concrete and the metal in a lifer. It is better than most other simple transmitters but it doesn't have a crystal like good transceivers. My transmitter is extremely clear. But it is very sensitive. Maybe you are talking too loud or are too...
  12. audioguru2

    22 W Audio Amplifier

    That is into 2 ohm speakers, at terribly clipped 10% distortion and with a very high 14.4V supply. It is a little less than 4W per channel into 4 ohm speakers just before clipping (low distortion) with a reasonable 13.2V battery.
  13. audioguru2

    max2606 FM transmitter/ipod dock

  14. audioguru2

    22 W Audio Amplifier

    Hi Dave, Welcome to our forum. The TDA1554 supplies 22W RMS each into two 4 ohm speakers at 10% distortion with a 14.4V supply. It gets hot so additional power heats it. So 44W will go to the speakers and about 22W will heat it. The total power is 66W and the max current at 14.4V is 4.6A. If...
  15. audioguru2

    Audioguru FM Tx

    My FM transmitter was in the open window on the 2nd floor of my house. My house is near the top of a hill. It transmitted a few hundred meters to my cheap Sony FM Walkman radio and more than 2km to my good car radio. Other houses in between blocked the signal which went the farthest with nothing...
  16. audioguru2

    Audioguru FM Tx

  17. audioguru2

    max2606 FM transmitter/ipod dock

    The MAX2606 is made for child's toys. Besides transmitting in mono, its radio frequency will drift all over the place and its sound will not have treble audio frequencies because the circuit doesn't have pre-emphasis which is the treble boost that FM radio stations have. On an FM radio the sound...
  18. audioguru2

    Cell Phone "AA" BATTERY Replacement...

    The voltage-boosting IC is a switched-mode power supply. Its oscillator grounds one end of the coil with the other end at the input voltage which builds magnetism in the coil, then releases the coil and it makes a "flyback" higher voltage which is stored as the boosted voltage. An ordinary...
  19. audioguru2

    Tunning

    The capacitance of any diode changes when the reverse voltage across it changes. Varactor diodes look like ordinary diodes but are designed to have certain amount of capacitance and the capacitance changes quite a lot when the voltage is changed. Car radios, VCRs and TVs use varactor diodes for...
  20. audioguru2

    fm

    Some simple FM transmitters have the antenna connected to a tap on the coil. Then things getting near the antenna don't affect the tuned frequency as much. The supply voltage also affects the tuned frequency. In my FM transmitter circuit the oscillator is supplied by a low dropout voltage...
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