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  1. audioguru2

    Convert Voltage

    1) Step-up the 7VDC/2A to 24V/0.47A with a switching power supply circuit having 80% efficiency. 2) Make a variable-frequency sine-wave generator. 3) Feed the sine-wave into a 60% efficient TDA2006 audio amplifier for a 7V RMS/1A sine-wave output. ;D
  2. audioguru2

    Coil gun charger circuit

    Hi MrHeckles, The circuit doesn't have "a 1uF capacitor between the 2N3904 transistor and the pot". It has a 0.1uF capacitor from the transistor's base to ground to hold a charge when the preset voltage is reached to keep the transistor turned on which turns off the 555 until the output voltage...
  3. audioguru2

    Coil gun charger circuit

    It should pass much more than only 8A. Its high resistance is limiting the current and heating it up. You need the Mosfet to be a switch, not a heater. Don't use a series resistor, it will waste even more power. Use a Mosfet with a much lower resistance like an IRFB20N50K. ;D
  4. audioguru2

    IR Remote Control

    What is a taster? Each pot's resistance changes the pulse width of the oscillator for their channel. The decoder's channel outputs feed servos that adjust their position according to the pot's resistance. The resistor connects between the points marked "X" to DC bias the input. The capacitor is...
  5. audioguru2

    IR Remote Control

    Did you connect the output of the encoder to the input of the decoder? Did you use a 10nF coupling capacitor and join the points marked "X" with a 1M resistor in the decoder like Harry says to do in his article? The circuits do not have anything to press. They are designed for model radio...
  6. audioguru2

    Led display Digital Voltmeter question

    Hi Jose, Yes, you can use it. The "S" indicates that its stability is improved. The "Z" indicates that it is made without lead. ;D
  7. audioguru2

    IR Remote Control

    The encoder circuit you found will sequence through one fixed and 6 adjustable frequencies, over and over. You can make it play a little tune. I don't know how it could be used for IR remote control. It could amplitude-modulate the IR beam with a transistor, then an IR receiver would play its...
  8. audioguru2

    Sequential Timers with PWM Motor Speed Control

    Hi Ante, Yeah, I'll borrow my son's digital camera and take pics and videos of my plane doing its tricks. I think it went straight up like a rocket because its battery was sliding toward the rear when it accellerated forward, so its balance was way off. I'll fasten it securely with chewing gum...
  9. audioguru2

    what is gate driver?

    A gate driver is a circuit that has a fairly high pull-up and pull-down current output so that it can charge and discharge the high gate to source capacitance of Mosfets very quickly. Gate driver ICs are available but frequently a pair of complementary (an NPN transistor and a PNP transistor)...
  10. audioguru2

    Coil gun charger circuit

    Hi Mr. Heckles, I think that your frequency is much too high for such a high value inductor and very slow diode "Fred". Your frequency is 43 times higher than the original circuit. It takes time for current to build in the inductor but your high frequency stops the current just after it has...
  11. audioguru2

    Electronic Stethoscope

    Hi again, I see that you are using single opamps but are using the wiring of the pins of dual opamps. They are completely different. They might be destroyed. I used a dual opamp because it is more popular and therefore costs less than a single one. ;D
  12. audioguru2

    Electronic Stethoscope

    Hi Aaron, Thanks for posting your schematic. I have corrected it for you:
  13. audioguru2

    Camping Music Box - PROJECT

    Hi Stuee, If you look closely at the spec's for Energizer's AA and D Ni-MH rechargable cells, you will notice that they are exactly the same capacity. Their D cell is simply an AA cell in a big D-size can! ;D
  14. audioguru2

    Trying something new for me.

    I think it would happen if the solar cell was in the shadow of a windmill or something. I just wanted to show that the diode and capacitor can make-up for the loss caused by flickering but they don't increase the current, they just allow double the solar cell's current for half the time to give...
  15. audioguru2

    Sequential Timers with PWM Motor Speed Control

    Hi Guys, I flew my electric model airplane today! ;D Its timers and motor speed control circuits worked TOO well. :( It was very windy so after setting its rudder for a big circle when gliding, I set the 1st timer for full power, the 2nd timer for half power and the 3rd timer for 1/4 power. I...
  16. audioguru2

    Trying something new for me.

    The diode and capacitor would raise the current if the sun was flickering on and of at a high rate. Without the diode and capacitor, a flickering sun's light on a solar cell would activate the solar cell only half the time so its average output voltage would be half what it should be. Therefore...
  17. audioguru2

    Electronic Stethoscope

    Hi Aaron, To post your picture, click on "Additional Options", click on "Browse", find and highlight your picture file then click "open". Your file's name will show in the Browse box then click "Post". ;D
  18. audioguru2

    Camping Music Box - PROJECT

    Hi Stuee, 100W would scare away the fish and anyone about 1km away. You need only a few watts for background music when fishing. Most amps you posted are designed for 4 ohm speakers and therefore have double the idle current of an amp designed for 8 ohm speakers. The stereo ones have double the...
  19. audioguru2

    transformer measuring

    Hi Autir, The answer is one or more of: 1) The value of the overloaded 4.9 ohm resistor changed by its very high temperature. 2) The internal resistance of the overloaded transformer changed by its very high temperature. 3) The core saturated in the overloaded transformer. You don't have...
  20. audioguru2

    Sequential Timers with PWM Motor Speed Control

    Hi Ante, Sure my model airplane is designed for radio control. I installed a hinged rudder with pushrod in mine. I didn't hinge the elevator nor ailerons yet. Mine is red but here's a white one:
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