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  1. audioguru2

    0-30V Stabilized Power Supply

    The original project is a kit. The kit maker must get a lot of complaints of it not working properly, many parts getting too hot and poor reliability.
  2. audioguru2

    0-30V Stabilized Power Supply

    Hi Effenburg, thanks for the comparison that shows both almost the same.
  3. audioguru2

    Polarity Switch

    All the idiots who are trying to make HHO for their cars should be banned from electyronic chat forums.
  4. audioguru2

    0-30V Stabilized Power Supply

    No. I simply fixed all the errors in the original project so the modified circuit worked perfectly and reliably. But the OPA445 opamps were expensive and frequently not available. The latest version uses common inexpensive opamps from either of two manufacturers. It is the same circuit but...
  5. audioguru2

    0-30V Stabilized Power Supply

    Both heatsinks are too small. The driver transistor has a tiny little heatsink.
  6. audioguru2

    0-30V Stabilized Power Supply

    The heatsinks look very small. When the current is set to max and the output is set to a low voltage with a heavy load or is shorted then the driver transistor and output transistors will get very hot.
  7. audioguru2

    0-30V Stabilized Power Supply

    Good! Your little transformer will be at its maximum rating when the output current from the project is 2.1A. The max voltage at 2.1A will be about 26VDC. So use a resistor that is 26V/2.1A= 12.4 ohms. It will dissipate 26V x 2.1A= 54.6W. Maybe you can find a heater that is the resistance needed.
  8. audioguru2

    0-30V Stabilized Power Supply

    Hi Karthikeid, The output voltage of your U2 opamp goes from 0V then suddenly switches to +28.5V. Do you have inputs pin 2 and pin 3 swapped? When the output of U2 is +28.5V then the base of the driver transistor is also +28.5V. Then the emitter of the driver transistor should be +28.0V which...
  9. audioguru2

    0-30V Stabilized Power Supply

    The 2N3055 transistor is an NPN. Measure the base-emitter diode then measure the collector base diode with the "diode test" of your multimeter. Maybe you have the pins mixed up. Look at the pins on the datasheet.
  10. audioguru2

    Brightest LEDs on the planet?

    You can buy extremely bright LEDs on E-Bay. The Chinese discovered that a dim old LED chip is extremely bright when its case focusses the light in a very small angle. But then it cannot be seen if it is not pointing directly at you. Light bulbs shine all around. Good LEDs shine almost all...
  11. audioguru2

    0-30V Stabilized Power Supply

    Then either the output transistors or driver transistor are not working or both 0.33 ohm emitter resistors at the emitters of the output transistors are missing.
  12. audioguru2

    0-30V Stabilized Power Supply

    U2 is an opamp that drives two emitter-followers. They have a voltage gain of slightly more than 3. What does the output of U2 do when you vary the voltage pot?
  13. audioguru2

    0-30V Stabilized Power Supply

    Check that the voltage adjust pot gives from 0V to +11.4V to the input of U2.
  14. audioguru2

    0-30V Stabilized Power Supply

    The voltage adjust pot gives from 0V to +11.4V to U2. U2 is part of the output amplifier that has a voltage gain of 3.08.
  15. audioguru2

    how can i charge a LiPo battery ?

    10C printed on the battery is not 10 Cells, it is the max allowed load current that is 10 times the rating of the battery. The battery is rated at 800mAh so it can have a max load current of 8A. The battery says for you to read its safety instructions. It will probably say not to charge it at a...
  16. audioguru2

    audio amplifiers

    The TPA3100d2 has many tiny pins that would be very difficult to solder. Adding a heatsink would also be very difficult. The sales sheet is wrong. It says that the output per channel is 20W into 8 ohms with a 12V supply but the datasheet shows only 7.5W to 10W per channel. It produces 10W per...
  17. audioguru2

    0-30V Stabilized Power Supply

    Hi Karthikeid, The current adjust pot should have a max voltage of only +1.7V so your +4.7V is much too high. It comes through a voltage divider from the output of U1 which should be +11.2V. Measure it. But the LED should not light because the output of U3 should be high. Measure it. Also...
  18. audioguru2

    0-30V Stabilized Power Supply

    U3 turns on the LED and makes the output voltage as low as 0V. With a 10M input resistance meter, measure its input voltages with the current pot set to max and no load. Use the negative wire of C1 for the negative meter lead.
  19. audioguru2

    stripboards?

    For many years I bought real genuine English epoxy-fiber-glass Veroboard. Then they stopped making it and their workers tried to make their own factory. So I bought a pretty good Chinese copy for a few years. Then The Chinese one became not available and I bought stripboard at a local store but...
  20. audioguru2

    0-30V Stabilized Power Supply

    The original circuit uses a 24V/3A transformer. Its max output is about 23VDC at 4.2A but the transformer will be overloaded very much. The transformer is rated at only 24V x 3A= 72VA. The original circuit is not calibrated properly to limit the current to 3A. The unregulated voltage is 34VDC...
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