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  1. duke37

    High Voltage Regulator Circuit Help

    The tube circuit you show looks good. There could be problems with stability as with any feedback amplifier. Do not exceed the power rating of the 6080. Great care is necessary in using correct units. Sloppy use has caused several disasters.
  2. duke37

    ? broken part found

    If it is connected between brown (live) and neutral (blue) then it is a noise suppresion X capacitor. Try and copy all the markings on it. If it is as I think then the amp will operate without it. It can't be very old with the new cable colours.
  3. duke37

    MOSFET switching problems

    Which was the winding that you reversed? Were you energising the transformer the same way with both fets or did you reverse the field? The half bridge seems to be more suitable for high voltages as the fet voltage is half the push/pull and the single primary winding eliminates leakage...
  4. duke37

    3W IR LED isn't very bright?

    If you wish to try the LED at higher output, then why not use two cells in series giving 3V and use a series resistance of about 1 ohm to limit the current? If it works, then you will need to obtain a suitable current source.
  5. duke37

    Generate 2ph 60cy 115/115v

    You will need to find out whether it is two phase or three phase with one phase earthed. The motor will have four poles for 2 Phase and three poles for three phase. Can you see inside? I attach circuits for producing two phase and three phase signals using CMOS.
  6. duke37

    MOSFET switching problems

    The diodes across the fets will need to handle the inductive current, they should be fast. This could be low or high if the transformer is saturating. Measure the input current with a scope to look for reverse current. Note that one fet should turn off before the other is turned on or you get...
  7. duke37

    Alarm reset timer

    You could connect the alarm via a time delay relay with the delay greater than the PIR reset time. How long does the alarm sound? Time delay relays are available or you could make a delay circuit to switch a standard relay.
  8. duke37

    High Voltage Regulator Circuit Help

    500MA. You don't do things by half ! Give us a specfication of your requirement including realistic current, voltages (fixed or variable) and ripple. What will the power supply be used for, a large amplifier should be able to manage 330V?
  9. duke37

    Generate 2ph 60cy 115/115v

    You will need two 60Hz inverters driven from a single frequency source and out of phase. This could be done with a higher frequency divided down or an analogue oscillator. Do you have the aircraft to go with it?
  10. duke37

    Relay Testing

    Your first post says that you are trying to test relays on a board. If this is true, then the resistances that you see could have nothing to do with the relays but due to resistances in the board. As has been said, the resistance should either be zero or infinity. I have seen poor contacts...
  11. duke37

    MOSFET switching problems

    It will accept energy but without knowing the transformer inductance and frequency it is not possible to say if it will accept it all without a significant rise in voltage. The only way that I can see to go forward is to run it at a safe level and measure both voltages and currents.
  12. duke37

    some damaged gadget chargers

    An engine driven generator can give the wrong voltage and wrong frequency. The faults may differ depending on what is wrong with the supply. There are two sorts of power supplies, one uses a mains transformer and the other a rectifier and a chopper circuit. You should find out the type and...
  13. duke37

    Capacitors DC in AC cts?

    As you say, you must not use polarised electrolytic capacitors. If you use plastic film capacitors which are not polarised, they normally have a DC maximum. For AC use, the voltage rating must be much higher. For 120V AC I would suggest at least 500V. There are capacitors intended for...
  14. duke37

    PLL synthesizer: Influence frequency resolution on loop bandwidth

    Not my area but this will not stop me! R gives the reference frequency and I do not see that it matters where this comes from. N is in the loop and so any delay here will be important.
  15. duke37

    PWM or SCR Motor Controller?

    I have designed a circuit to drive a 12V DC motor for a coil winder. I have had some of this working but have added things which have not been tested. I am busy at the moment so this will have to wait. It uses the back EMF of the motor to measure the speed and will give a pulse if it running...
  16. duke37

    Circuit Breaker for Model Railroad

    If the motor runs in both directions, then you cannot use a diode across it. You could however use a pair of zener diodes connected back to back to limit voltage spikes.
  17. duke37

    MOSFET switching problems

    If you have no load, the inductive energy has to be returned to the supply via the diodes in the fets. You could try better external diodes across the fets Will the supply accept this energy?
  18. duke37

    The Ultimate Tube RIAA-Amplifier?

    p.gabr That looks like an excellent match. Is your curve a measurement or simulation?
  19. duke37

    Pressure Effect

    The fuel tanks on space rockets are only a few thou thick, they need internal pressure to keep them in shape, they will not stand any external pressure. An extreme example. I had another thought, water is more or less incompressible but CO2 gas is not. Will the gas at 1700 psi have a density...
  20. duke37

    Pressure Effect

    With internal pressure of 800 psi and external pressure of 1500 psi, the likelyhood is that the container will buckle and the internal pressure will rise but there will be no avaiable gas to raise the buoy. CO2 is highly water soluble, hence fizzy pop.
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