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  1. audioguru2

    0-30V Stabilized Power Supply

    R21 feeds the voltage across R7 into the inverting input of opamp U3 so that U3 can integrate the voltage with R21 and C8. The original circuit used a 1W resistor that dissipated 0.37W. The LED's resistor is R22 and is 3.9k. It has 28V across it now when the LED lights. Then it dissipates (28V...
  2. audioguru2

    0-30V Stabilized Power Supply

    Ohm's law says that "The voltage developed across a resistor is made by the current in the resistor times the resistor value". 2A in the 0.47 ohms of R7 produces (2A x 0.47 ohms=) 0.94V.
  3. audioguru2

    11.1 volts to 8.0 volts ?

    Your idea is completely wrong and will not work. The datasheet for the LM340 regulator shows its current boosted with a PNP power transistor and a current sensing resistor. But the simple circuit needs another transistor added for current limiting and its minimum input voltage is about 10.5V...
  4. audioguru2

    11.1 volts to 8.0 volts ?

    The datasheet for the very old IRF510 Mosfet shows that it needs a gate-source voltage of 10V (not 8V) to fully turn on. Maybe you should be using a "logic-level" Mosfet instead. Your Mosfet does not do anything since it is always turned on like a piece of wire. An ESC uses...
  5. audioguru2

    0-30V Stabilized Power Supply

    The 2N3055 output transistors are powered from about 41V. If the output is 12V then the output transistors have 41V - 12V= 29V across them. Simple arithmetic calculates that they heat with 29V x 2.5A= 72.5W. If the current is set to 3A and the output voltage is low or is shorted then the output...
  6. audioguru2

    0-30V Stabilized Power Supply

    I am glad that you spotted the problem and it caused no damage.
  7. audioguru2

    0-30V Stabilized Power Supply

    U1 is a simple voltage reference. It uses an opamp U1 to amplify a 5.6V zener diode to 11.2V:
  8. audioguru2

    0-30V Stabilized Power Supply

    Connect a load of 2.7k ohms/0.5W to the output of the project. Opamp U2 and the driver and output transistors are an amplifier with a voltage gain of 2.68 times. So when the voltage setting pot is set to maximum it has +11.2V from U1 going to the input of U2 and the amplifier amplifies it to...
  9. audioguru2

    Quenstion about resistor around transistor(HELP)

    I typed detailed answers to your questions twice but my computer jumped pages which deleted them. It looks like you must learn about the basics of electronics and the basics about transistors. Your calculation of 4.2V/330 ohms is WRONG at 127mA. The correct answer is 12.7mA. You found a very...
  10. audioguru2

    0-30V Stabilized Power Supply

    A 2N3055 has an allowed continuous collector current of 15A. A 2N3722 has an allowed continuous collector current of only 1A but it should work if the load current is 1A or less and if it does not get too hot. I could not find a datasheet for the 2N3722 to see which pin is which. Maybe you have...
  11. audioguru2

    0-30V Stabilized Power Supply

    Since you used only one output transistor then it sounds like you made the original circuit that has many errors instead of making the improved and fixed circuit that has two 2N3055 high current output transistors to share the heat. The new driver transistor is much better than the old one. I...
  12. audioguru2

    Inverter oscillator

    Kevin, your .68K capacitors are not 680uF. Instead they are 0.68uF which is 680nF. 5M x 0.68uF= 3.4 seconds. The K indicates a tolerance of 10%. Your circuit is almost the same as my Standard Cmos Inverters Oscillator when I turn it around. Except it has an extra resistor and extra capacitor...
  13. audioguru2

    0-30V Stabilized Power Supply

    Yes, I said 5.6mA instead of 5.6mV.
  14. audioguru2

    0-30V Stabilized Power Supply

    Yes, if the DAC in the PIC has an output from 0V to 5.0V then to get 11.2V the gain of another opamp must be 2.24. The current-setting pot has an output of from about 5.6mA for an output max of a few mA to 1.41V for an output max of 3A, then an extra opamp is not needed. 
  15. audioguru2

    0-30V Stabilized Power Supply

    The existing voltage-setting and current-setting pots are fed from 11.2V. But most digital pot ICs have a maximum of 5V. Then the project must be re-designed for them to be used.
  16. audioguru2

    Inverter oscillator

    The capacitor charges and discharges with alternating current that goes positive then it goes negative. Here is a sketch of the waveform at the capacitor:
  17. audioguru2

    Inverter oscillator

    What voltage will double? The supply voltage? How can it double? Where is your schematic and parts list?
  18. audioguru2

    Inverter oscillator

    Since you did not post a detailed schematic then we do not know what you are talking about. You didn't even say if the inverters are TTL or Cmos, and did not say their part number.
  19. audioguru2

    Inverter oscillator

    There is no "gate discharge resistor". The phase shift of C1 and R2 sets the oscillator frequency and R1 limits the current into the input protection diodes so that the voltage at C1 can swing higher and lower than the supply voltage without changing the frequency.
  20. audioguru2

    Inverter oscillator

    An old TTL logic device is bipolar. Most TTL inverter oscillators use a crystal, not an RC network. A Cmos oscillator can use an RC network for a fairly accurate frequency. Ordinary inverters can be used or a single Schmitt-Trigger inverter. I do not know what you mean when you say "0V sink...
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