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  1. audioguru2

    hydroxy gas power supply/separating oxygen and hydrogen from water

    Sodium bicarbonate is where the sodium yellow flame is coming from.
  2. audioguru2

    hydroxy gas power supply/separating oxygen and hydrogen from water

    Sodium burns with a yellow flame. Hydrogen burns with a nearly invisible light blue flame.
  3. audioguru2

    white led

    The 3.9 ohm resistor sets the regulated current to 325ma if there is only one of if there are many LEDs in series. With only one LED then a higher voltage will be across the LM317 causing it to heat more.
  4. audioguru2

    Electronic Stethoscope

    Hi Jrnb, I don't know which pspice software you are using. Your 741 has the correct power supply but it has no negative feedback so its gain at DC and at very low frequencies is about 200,000. The 741 cannot drive resistances as low as R14, R15 and R17.
  5. audioguru2

    Problem With Ultrasonic Motion Detector

    If you showed the component side of the pcb then the BC639 is correct.
  6. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    I forgot about the 0.22uF cap in series with the 100 ohms. A ceramic disc capacitor would work well.
  7. audioguru2

    Electronic Stethoscope

    Yes. the frequency response is down to about 6.1Hz. No. The signal causes fluctuations in the supply voltage (when the internal resistance of the battery increases as it runs down) if the 470uF capacitor is not there to smooth the fluctuations. A heartbeat is a DC pressure wave. A microphone...
  8. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    I talked about adding one 0.1uF ceramic disc capacitor across the supply for the ICs. It is ceramic which does not have polarity so it is for AC or for DC.
  9. audioguru2

    Problem With Ultrasonic Motion Detector

    You used the wrong crystal frequency. Does the 40kHz ultrasonic transmitter have any output at only 32kHz? Does the 40kHz ultrasonic receiver receive anything at only 32kHz? Do you use water instead of gasoline to power your car? Do you add gasoline instead of water to a car's battery? Maybe...
  10. audioguru2

    insect attach

    I think he wants to attach an insect in (inside?) a spring. Then it can bounce around all over his room. It must be a pretty big insect (a tarantula?) or it is a very small spring. He wants a good circuit "for insect". A stereo or a TV? It is the king of insects.
  11. audioguru2

    SERVO THROTTLE SIGNAL

    Reverse the connections to the motor with a relay. I have seen many model airplanes and cars, but I have never seen one go backwards.
  12. audioguru2

    insect attach

    "Insect attach in spring?" Sorry, you cannot speak English. Maybe the insects are attacking you in the springtime. Electronic circuits won't stop the insects unless you have a very high voltage to zap them.
  13. audioguru2

    SERVO THROTTLE SIGNAL

    Ho Kain, Model aircraft, cars and boats use PWM to control their motor's speed in an ESC circuit. A pulse width of 1ms imakes the motor stop or run very slow. A pulse width of 2ms makes it run very fast.
  14. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Kachew is not making a square-wave inverter. He is making a modified sine-wave inverter with the correct values of R and C for a CD4047 IC and is using a CD4001 to gate the outputs into a modified sine-wave.
  15. audioguru2

    Two PCBs off of one power source

    The 10k resistor between pins 4 and 5 of the MV34119 has colour bands brown, black then orange. Then the circuit has a signal gain of 7. Maybe you used a 100k resistor instead which makes a signal gain of 61. A 100k resistor has colour bands brown, black then yellow. Then the volume control...
  16. audioguru2

    12v to 230 volts dc with voltage doubler circuit its possible?

    A voltage doubler circuit with capacitors and rectifiers is for very low current loads. A transformer is much more efficient for a power inverter.
  17. audioguru2

    Two PCBs off of one power source

    Then the volume control resistance is cracked. When its slider is above the crack it is much too loud. Below the crack is nothing. The amplifier for the MC34119 should be like this:
  18. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    The max supply voltage for most CD4047 and CD4001 ICs is 18V but Texas Instruments has 22V. A 16V zener diode has a 5% max voltage of 16.8V so it will keep the supply to the ICs from going higher. The capacitor smooths fast supply pulses and the 47 ohm resistor reduces the max current through...
  19. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    I peeked at the hard drive of my old 486 computer. It has the original Low Cost 500W Inverter's schematic. I thought so! The original designer used 100 ohms in the oscillator to make the frequency of his inverter 50Hz because the on resistance of the Cmos was too high for his too big capacitor...
  20. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    A 0.1uF 5% capacitor and a 47k 5% resistor produce a frequency of 45Hz to 55Hz. The Cmos has an on resistance of about 500 ohms in series with the resistor which reduces the calculated frequency by only 1%. Your 4.7uF 20% capacitor and a 1k 5% resistor produce 29Hz to 42Hz because the on...
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