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  1. audioguru2

    DC MOTOR CONTROLLER

    Hi Alun, Deja vu? I used a voltage regulator for my circuit's PWM oscillator so that the motor's speed would remain constant as the battery voltage ran down, then a 3rd opamp as its comparator operating at the full supply voltage for plenty of Mosfet gate voltage. Your circuit would also need a...
  2. audioguru2

    A chock coil

    We think its value doesn't need to be so high but this author of an FM transmitter likes to use it as a collector load impedance:
  3. audioguru2

    IR photodiode

    This article explains photodiodes very well: http://www.udt.com/Datasheets/Other/PhotodiodeCharacteristics.pdf
  4. audioguru2

    A chock coil

    Hi Walid. It is called a choke, and if its value is too high then the capacitance between the layers of windings might be so high that it parallel resonates at a lower frequency than you want. Above its resonance it behaves like a capacitor instead of an inductor.
  5. audioguru2

    DC MOTOR CONTROLLER

    I used that motor speed control circuit in my electric model airplane and it works very well.
  6. audioguru2

    100 uH coil

    Yes I did and I replied with a link to millions of these thingys:
  7. audioguru2

    100 uH coil

    Hi Staigen, You are absolutely correct! My coils are only 100nH. I think Walid recently posted an FM transmitter circuit using 100uH by mistake and I didn't notice its error. :-[
  8. audioguru2

    DC MOTOR CONTROLLER

    Hi Guys, If the circuit is corrected by adding a diode, by using the spare gates in the Cmos IC in parallel with the existing one to drive the Mosfet with much more current and using a 12V supply, it will control the speed of a powerful motor and will also make a pretty good lamp dimmer. No...
  9. audioguru2

    100 uH coil

    Hi Staigen, Didn't you see my FM transmitter? I found some tiny variable caps to tune it, it has a low-distortion preamp with proper selectable pre-emphasis, the preamp and oscillator have a low-dropout regulator, it has an RF amplifier/buffer so that it doesn't change its tuning if something...
  10. audioguru2

    MIC coupling capacitor

  11. audioguru2

    100 uH coil

    I use this on in my FM transmitter:
  12. audioguru2

    How can this circuit improve 0...30V???

    It is very similar to our 0V-30V project. It has a simple current limiter instead of an adjustable current regulator, and uses an extra transistor and resistor to turn on the output transistors. The opamp turns them off in this circuit. It is good that it has a switched input voltage to avoid...
  13. audioguru2

    DC MOTOR CONTROLLER

    I think the author likes warm Mosfets. Cmos operating with a supply of only 6V has an output current of about only 2mA. It will take a long time for only 2mA to fully charge the high gate capacitance of a power Mosfet. I think the author likes hot Mosfets. I think the author likes melted Mosfets...
  14. audioguru2

    0-30 Vdc Stabilized Power Supply

    P1 controls the voltage and P2 controls the current. They are completely separate but the project's output voltage is reduced by the current regulator. Make it with the pots and measure the voltages at the pots. Then program your DACs to produce the same voltages. You don't want to use your...
  15. audioguru2

    DC MOTOR CONTROLLER

    Hi Staigen, Have you seen this "PWM" motor speed control circuit in our projects section? http://www.electronics-lab.com/projects/motor_light/033/index.html It looks like just a variable frequency oscillator to me. I think the motor's speed would remain the same about half, but it would buzz at...
  16. audioguru2

    Datasheet for 3038 fuction generator

    Hi Alun, If you are nice to Maxim, they might ship you a free sample. ;D
  17. audioguru2

    Antenna and TV standard

    Hi Mark, Do people still use TV antennas where you are? In my city, nearly everyone has cable or satellite TV. They were 300 ohms for the 1st million years, but maybe you can buy them today at 75 ohms to match coax cable to the TV. Look on Google for my story about the TV antenna I had about 35...
  18. audioguru2

    Wireless telephones

    Hi Walid, Here, http://electronics.howstuffworks.com/cordless-telephone.htm is a pretty good explanation of the history of cordless phones in America. There are many different ways of modulation over the years and I think they are wrong about the 1st cordless phones: My 1st cordless phone used...
  19. audioguru2

    IF transformers

    Me too, but I think he means for Walid to test those spec's of the transformer. It would be a pretty big job. I would just purchase a transformer I needed and maybe replace it later with the unknown one to see if it works. ;D
  20. audioguru2

    I get a problem of 0-30 Vdc Stabilized Power Supply

    Hi Cyw, Have you seen our discussion of this project to stop it from "thermal meltdown" and to make it work properly? http://www.electronics-lab.com/forum/index.php?topic=128.0 The output stage has a gain of R12/R11 + 1 = 3.074 so with an accurate 10.0V replacing P1 and if the resistors are...
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