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  1. audioguru2

    0-30V Stabilized Power Supply

    I have Picmaster's schematic of 10/10/2010 and it says 5A but it has only two 2N3055 output transistors that will fry. It might have other problems.
  2. audioguru2

    0-30V Stabilized Power Supply

    The 3A version uses two output transistors. Each emitter resistor has a max voltage of 1.5A x 0.33 ohms= 0.5V across it. When the output voltage is shorted or is low then each output transistor heats with (30V - 0.5V) x 1.5A= 44.25W.     The 5A version uses three output transistors. Each...
  3. audioguru2

    0-30V Stabilized Power Supply

    I guess nobody replied is because we cannot understand your broken English. 1) "Remove AC source". Turn it off? 2) "Direction". North, south, east or west? 3) "Applied DC solution". DC applied to what? Solution of what problem?
  4. audioguru2

    Need help to identify potentiometers, please

    Lacquer thinner will probably dissolve plastic parts in a pot and deposit it as a mess all over the resistive track. My contact cleaner is "safe on plastics, leaves behind zero residue and is fast drying". Why not use it?
  5. audioguru2

    0-30V Stabilized Power Supply

    Hi Red Baron, I have Picmaster's schematic, revision 2.10 dated 10/10/2010, which is almost the same as mine. It uses TIP3055 output transistors instead of 2N3055 ones. The TIP3055 has an epoxy case, not metal and is rated at 90W max instead of 115W max so one might be shorted C to E due to...
  6. audioguru2

    0-30V Stabilized Power Supply

    I think there is a certain supply voltage where the opamps in the project suddenly begin working, maybe with severe overshoot. maybe why most audio amplifiers do not have soft start. Instead they use a relay for delayed start so that the circuit can stabilize before it has an output.
  7. audioguru2

    New Power Supply

    The fast TLE2141 opamp needs to have a couple of compensation capacitors (like the long posted project) so that the phase shift from the slow 2N3055 transistor does not cause oscillation. The opamp will not fry if it oscillates because it does not have a high current load.
  8. audioguru2

    New Power Supply

    I think a TL2141 opamp driving the amplified output section will oscillate because the slow 2N3055 output transistor delays the negative feedback. The single output transistor will get fried if the output voltage is low or shorted and the current is high.
  9. audioguru2

    Need help to identify potentiometers, please

    I use "contact cleaner" to fix scratchy sounding pots. Sometimes a coupling capacitor leaks DC current into a pot that makes a scratchy sound that is fixed by replacing the capacitor.
  10. audioguru2

    0-30V Stabilized Power Supply

    The original project has errors and problems: 1) Many of its parts are overloaded so it is not reliable. The transformer, driver transistor and single output transistor overheat. Your 24V/3A transformer is rated at 72VA maximum but the full wave bridge rectifier operates from the peak which is...
  11. audioguru2

    0-30V Stabilized Power Supply

    I removed R15 from the original circuit because it wasted some important voltage headroom. I removed D10 because I saw no purpose for it. Try adding D10 back. Can you try a non-inductive resistor for the current sensing 0.47 ohms?
  12. audioguru2

    0-30V Stabilized Power Supply

    I suspect that the inductance of the 0.47 ohm resistor and the 10uF output capacitor cause the darlington connected driver and output transistors to ring at about 10MHz when the power is turned off. Maybe the emitter of the clamp transistor should connect to the output ground on the other side...
  13. audioguru2

    0-30V Stabilized Power Supply

    I have not made this project. I make many circuits on stripboard instead of on a pcb then half the wiring are the parts and a few jumper wires. In my electronics career I made custom one-of-a-kind circuits (some were very complicated) and the prototype made on stripboard worked perfectly and...
  14. audioguru2

    0-30V Stabilized Power Supply

    I gave your white schematic as much contrast as is possible which caused its background to be a little grey. I noticed that you changed most of the parts designation numbers so that when most of the other schematics used R11 and R12 to set the gain of the voltage amplifier now you have R18 and...
  15. audioguru2

    0-30V Stabilized Power Supply

    I downloaded it and tried to make it a positive image instead of a negative black image. Then many of the lines are not shown. There is some garbled text on it:
  16. audioguru2

    0-30 volt regulated power supply

    I answered you and another kid in your class about your crippling of this project on another website. Earlier today I saw this schematic that uses a 20k fixed resistor for R12 instead of a trimmer resistor. The trimmer resistor changes the voltage gain to allow an output as high as 30.0V. With...
  17. audioguru2

    soaked capacitor

    Your soldering looks bad. It should look smooth and shiny. Did you use plumber's solder? Maybe your soldering iron is too small to solder those big wires. A shorted capacitor does not hold a charge. Its charge quickly discharges through the short. Charge it then use a high input resistance...
  18. audioguru2

    0-30V Stabilized Power Supply

    On the other website you wanted to remove its current regulation. Then it will blow up and will be destroyed if its output is shorted or has a current higher than 3A.
  19. audioguru2

    query in the usb charger

    When a charger or power supply has no load then its power consumption is very low. If you detect that it has no load and disconnect it then the new detect/disconnect circuit might waste more power that you save.
  20. audioguru2

    how measure fuel level in bike as digitally

    What powers your bike? We don't know what powers your bike because you did not tell us. My bike is powered by my legs. Maybe your bike is powered from a battery, gasoline or diesel fuel. Maybe a steam engine with coal on fire?
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