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  1. duke37

    Ashdown Peacemaker 40

    Possibly a flashover in a power supply capacitor.
  2. duke37

    Base resistor and MOSFET + Rectifier Diode Selection for Solenoid actuation?

    I am not going through your TIP120 calculation, I have a scope to repair. I have not used logic level MOSFETs, you can look up the data. A common family of 3A diodes is 1N540x
  3. duke37

    Base resistor and MOSFET + Rectifier Diode Selection for Solenoid actuation?

    You have shown a NPN transistor, not a MOSFET. Which one do you intend to use? The current through the solenoid can be calculated I=V/R. You seem to have this right. The base current will be less than this by the current gain of the transistor which could be as low as 10. It certainly will not...
  4. duke37

    Can someone identify this component?

    I was given one fencer to repair where the output pulse had been rectified with a long string of high voltage diodes. These had all been blown apart by lightning. Replacing these cured the problem. I do not understand the advantage of this, I doubt if the fence is sufficiently insulated to hold...
  5. duke37

    Can someone identify this component?

    Capacitors do not store power, they store energy. This energy can be used at high power for a short time or lower power for a longer time. The energy stored is C*V*V/2 so if you have 10 times the voltage, you need 100 times the capacity to store the same energy. The choice of capacitor and...
  6. duke37

    Can someone identify this component?

    If the capacitor is charged to 250V, then it will hold 0.3J which is significant for a battery driven fencer. Mains driven fencers can go up to 10J and will supply miles of wire but I would not go near them.:) A common way of triggering the switch (SCR?) is using a diac which triggers at about...
  7. duke37

    Can someone identify this component?

    It would be nice to know what the power supply is. A common fencer charges up a capacitor (C8) and then discharges it through a transformer to produce the high voltage. One of the transformers will be used to charge the capacitor and one will be connected to the output. There seems to be a SCR...
  8. duke37

    Electrolytic capacitors: Opinion required please

    All acids are ionic and conductive. If they leave a wet deposit then that will be conductive. Wash it with water, then de-ionised water, then IPA. Dry. Only use cored solder made for electronics use
  9. duke37

    Voltage Reduction

    If the old power supply is 12V and you replace it with 24V, then things could go bang. The buzz in the old supply may be reduced if you tightened up the transformer laminations and made sure it is bolted tightly to the chassis. You could try heating the transformer gently in an oven and then...
  10. duke37

    Ok To Bridge Left & Right Channels Together?

    Sorry about getting it wrong, I saw an arrow pointing upwards TO IPOD. I would not have been mislead if the arrow pointed downwards and labeled FROM IPOD.
  11. duke37

    How to create 3D omnidirectional antenna set?

    A loop is where the aircraft is nosed up and goes over the top. A roll is where the aircraft flies in a straight line but tips upside down and continues until it is fying level again. I have not seen a drone and do not know what aerodynamics they are capable of. Helicopters and even a Boeing...
  12. duke37

    Ok To Bridge Left & Right Channels Together?

    I would use a resistor (1k?) on each stereo output so that left does not directly drive right and vice versa.
  13. duke37

    Regular epoxy adhesives for heat sink?

    Epoxy will glue the devise to the heat sink and you will not be able to dismantle it, should it go wrong.
  14. duke37

    How to create 3D omnidirectional antenna set?

    If the polarisation is not exact, then there will be a sine wave error. I.E. not much difference initially but going to zero at 90 degrees. Do you do loops or rolls?
  15. duke37

    Gas diffusion - a question or two

    Or add a double glazed pane inside the existing window with a largish gap for sound proofing. I did it cheap 50 years ago, will consider doing it again in another 50 years.:)
  16. duke37

    How to create 3D omnidirectional antenna set?

    A vertical dipole will give a vertical polarised omnidirectional output. A pair of horizontal dipoles mounted in a horizontal cross at 90 degrees and fed with signal at 90 degrees will give a horizontal polarised omnidirectional output. Some FM aerials are made as a loop, called a halo, to...
  17. duke37

    Gas diffusion - a question or two

    I doubt if you can make a reliable seal using wood which is permeable. Do not confuse humidity with moisture content, temperature also comes into it. Grain is dryed with only a few degrees increase in the drying air. Your house will be dry inside because the temperature is higher than outside...
  18. duke37

    Gas diffusion - a question or two

    For optimum heat resistance I believe that 3/4 inch is best. Less than this there is less gas insulation and more than this there is gas circulation - convection. Wider spacing is better for sound insulation and I would think that heavy glass would be better than lightweight perspex. To...
  19. duke37

    Diode and transistor failure

    Check the brushes, commutator and armature for condition.
  20. duke37

    RC receiver failure

    I do not think that the MOSFET body diode will act as a flywheel diode, the polarity is wrong. Some MOSFETs are specified on the amount of energy they can absorb when turning off. Flywheel diodes will help to reduce this energy.
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