Search results

  1. audioguru2

    Electronically controlled 12V 75W lamp

    Hi Simian, Those LEDs have the narrowest only 10 degrees angle I've ever seen. You might be riding at night and ride over a critter or small child coming from out of the narrow beam. I guess you could tilt each LED a little to make the beam wider (but then dimmer). The battery cell's capacity...
  2. audioguru2

    Electronic Stethoscope

    Hi UH, The LM386 is a linear non-inverting power amplifier with built-in negative feedback for a voltage gain of 20. It also has built-in internal biasing so that its inputs work at ground which is its negative supply voltage. Its datasheet is here: LM386.pdf
  3. audioguru2

    Electronically controlled 12V 75W lamp

    What kind of 6V battery? What max current for the LEDs?
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Zama, Welcome to our forum. ;D What did you use for a load that killed it? Did you make the original project or the modified and improved one?
  5. audioguru2

    Power Supply - looking for 200pf capacitor

    Mixos, the owner of this site and many others have built the original project and reported that it doesn't produce anywhere near 30V at 3A and some of its parts get extremely hot.
  6. audioguru2

    time beeper

    Thanks Mp, you are correct. This project would be reliable for a long time if it used an expensive 3.2V Lithium battery like Palm Pilots have. Look at Energizer's expensive AA lithium cells. Their 1.6V stays high over most of their life unlike "ordinary" AA battery cells. This project could even...
  7. audioguru2

    Quick AC question

    Hi Um...Me, In your 120VAC/60Hz system, black is the live wire and white is the neutral which is grounded at the power source. You should switch the black live wire and connect together the white wires because then when a switch is off its receptacle is dead. The way you have it, the receptacle...
  8. audioguru2

    Ignition coil driver circuits and experiments

    When you parallel the coils, connect one of them with its terminals opposite the way the other one is wired to make them opposite phase. Maybe car ignition coils don't have the polarity of their primary terminals marked, so you would need to try it then reverse the connections to one of the...
  9. audioguru2

    Ignition coil driver circuits and experiments

    Hi Steven, Can you wire the spark coils in parallel but in opposite phase, so that one produces +25,000V and the other produces -25,000V? Then you would have a long 50,000V spark jump between them.. ;D
  10. audioguru2

    phase inversion

    A common-emitter transistor inverts a signal because of the action of Ohm's Law at its collector resistor: 1) In an NPN transistor, its base is a P type and emitter is an N type of silicon so a positive-going signal at the base increases its base current. 2) An increase of base current in a...
  11. audioguru2

    0-30 Vdc Stabilized Power Supply

    Pin 2 of U# is connected to the output 0V which is connected to the rectifier's 0V through R7. Check your wiring.
  12. audioguru2

    Universal battery charger

    The actual value doesn't matter. It filters noise from the battery if it is loose in the connector and provides a small delay.
  13. audioguru2

    LM324, LM358 crossover distortion

    In the datsheet of Mitsubishi's copy of National's LM358 low power dual opamp (half an LM324 quad), a very good description is made about why and how much crossover distortion is caused, and a method to reduce it. They show an awful full output frequency bandwidth to only about 6kHz at 10%...
  14. audioguru2

    Bass Extender

    Are you thinking about getting a subwoofer and amplifier for it to add more deep bass to your sound system? Years ago I wasn't satisfied with the "ordinary" bass output from my sound system at home that uses pretty good manufactured speakers with 8" woofers and some speakers that I made myself...
  15. audioguru2

    What is "tunable ferrite"?

    What frequency is this transmitter? It looks similar to the circuit in the transmitter of a cheap RC toy car but its low tuning parts values might tune it to a harmonic of the 27MHz crystal.
  16. audioguru2

    Lowpass filter for subwoofer

    Hi Dakshitha, Welcome to our forum. ;D This project won't boost the bass of your sound system. It is designed to cut high frequencies at a frequency determined by its pot setting, and pass very low frequencies to a separate additional amp that drives a subwoofer speaker. The volume control on...
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Smitjuh, The current regulator, U3, is used as a comparator with overall feedback through the entire voltage regulator. Its reference voltage from the pot is referenced to the rectifier's common voltage and one side of R7. Its input pin 2 is connected to the project's output's 0V terminal...
  18. audioguru2

    DSB power

    There aren't any scientist animals around anymore. They were replaced by marketing folks who know nothing about anything. ;D
  19. audioguru2

    About Led Display

    Are you selling this stuff? I can buy one at a local store. It is mounted on a big belt-buckle and many kids wear them displaying their name or swearing words that scoll brightly. Their price is $50.00CAN.
  20. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Smitjuh, Welcome to our forum. ;D It is good to hear that your project works. Did you make the original or the modified one? You should be able to adjust the voltage from very close to 0V all the way to 30V. The current regulator is supposed to reduce the output voltage and light the LED...
Top