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  1. audioguru2

    1-25 volt power supply

    No Kevin. It is a perfectly normal power supply circuit with good voltage regulation and it has current limiting. 1) Rz powers the LM385-2.5 which is a good 2.5V voltage reference IC. 2) The opamp drives a TIP121 darlington transistor rated at 5A as a follower. 3) R1 and R2 are a voltage...
  2. audioguru2

    1-25 volt power supply

    There is no problem with our fixed circuit. The output of the circuit is connected directly to the inverting input of the opamp so the output of the circuit has a voltage exactly the same as the voltage at the non-inverting input of the opamp. Then the gain is exactly 1.
  3. audioguru2

    1-25 volt power supply

    Hero, you have the darlington base shored to its emitter. It should be like this:
  4. audioguru2

    1-25 volt power supply

    It is almost the same as the other circuit. Why does it have two opamps? One opamp has a gain of about 200,000 which is plenty of gain for it to be the error amplifier. One opamp will need to be a non-inverting amplifier. Also, the simple circuit has nothing to limit the output current.
  5. audioguru2

    extending an CFL electronic ballast

    ALL household compact fluorescent light bulb circuits I have seen show 4-pins glass bulbs. They have a filament at each end to heat the gas and reduce the starting voltage. Sams talks about a 2-pins glass bulb with a starter that shorts it then opens when it heats. The ballast makes 500V to...
  6. audioguru2

    2 pin compact fluorescent lamp to 4 pin socket?

    Are you trying to kill bugs with UV? The 36W glass light looks like two 2-pins lights side-by-side. No filaments.
  7. audioguru2

    2 pin compact fluorescent lamp to 4 pin socket?

    I have some modern CFL light bulbs that have burned out. Their glass coil has 4-wires, not 2-wires and there is a filament at each end the same as those huge old glass fluorescent tubes. I saw 2-wire CFL glass lamps about 18 years ago because my daughter had one for her desk light.
  8. audioguru2

    extending an CFL electronic ballast

    The photo on the ballast shows two CFL bulbs with 4-wires each. But your OLD CFL bulbs have only 2-wires each. The ballast starts the bulb by heating its filament at each end. Your OLD bulbs do not have filaments, they are started with an OLD starter thingy that creates a high voltage spike...
  9. audioguru2

    analog electronics

    Your English is horrible. Why not ask in your own language on a website in your country?
  10. audioguru2

    2 pin compact fluorescent lamp to 4 pin socket?

    A 4-pins compact fluorescent lamp tube has a filament at each end for starting. A 2-pins compact fluorescent lamp is probably VERY OLD and used a huge and heavy inductor as a ballast to provide a high voltage spike to start. It is too bad that you bought old junk from e-bay.
  11. audioguru2

    Circuit analysis

    R2 and the signal's source impedance form a voltage divider. C2 and the signal's source impedance form a lowpass filter. R3 and R4 form another voltage divider that loads down the first voltage divider. C3 and R3 form a highpass filter. R3 and C4 form another lowpass filter. The signal's...
  12. audioguru2

    doubt in active device

    A diode DOES NOT produce energy. Instead a battery or a generator produce electrical energy. A diode is a rectifier. Why do you not understand?
  13. audioguru2

    [answered] about 555 circuit

    I answered this question in the forum on the other website. Look at the datasheet for the LM555 that tells you all about it.
  14. audioguru2

    voltage across capacitor

    R2 and the 12V battery charge C. The voltage across C will be almost 12V when C is almost fully charged.
  15. audioguru2

    doubt in active device

    A diode does not produce power. A battery or a generator produce power. A diode is a rectifier to convert AC into DC.
  16. audioguru2

    0-30V Stabilized Power Supply

    R21 simply allows C8 to slow down the switching of U3. Instead increase the value of R17 so that the LED does not turn on when there is a small output load.
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    You forgot to calculate that the single 2N3055 output transistor and the tiny 2N2219 driver transistor will melt if the output current is 3A and the output voltage is low or is shorted. 36VAC produces a peak of 50.9V which causes the positive unregulated supply to be 48.9V. Then the output...
  18. audioguru2

    0-30V Stabilized Power Supply

    You did not say if the current regulation LED is on all the time or only if the current-setting pot is at zero and there is no load. Opamp U3 is simply a comparator. Resistor R7 is simply a current to voltage converter of the load current. When the voltage produced by the current-setting pot...
  19. audioguru2

    0-30 Vdc Stabilized Power Supply

    Since you are only interested in simulation, not the real circuit then did you try a voltage regulator IC like a 78L05?
  20. audioguru2

    0-30 Vdc Stabilized Power Supply

    Xwasx, You are asking for your project to fail because you have a tiny low power 2N3904 transistor for Q2 and only a single 2N3055 for Q1. The datasheet for a 2N3055 shows that with an output of 4A its minimum hFE is 20. A graph shows that its hFE is typically 35 at 2.5A but is typically 55 at...
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