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  1. duke37

    LED setup help needed.

    The CMOS 4017 Johnson counter may do what you want with a transistor to drive each LED. You will need a 5 to 15V supply.
  2. duke37

    Hartung amplifier project

    You can have as many opinions as you like but these will not help. You need to know whether the black labelled wires are intended to be connected together or they are start (or end). I would guess they are the start. One way to find out would be to put the mains into the 250V output winding and...
  3. duke37

    Vintage Schematic Questions

    I may have expressed myself poorly. I did not intend to add an extra load to drop the voltage. The 470Ω resistor which I suggested would be in series with the diode. This will reduce the HT voltage, reduce the ripple and reduce the heating in the transformer. The resistor value should be chosen...
  4. duke37

    Homemade Coil Help

    Measure the resistance of the primary and secondary to check for continuity. This will not enable shorted turns to be detected. This can be done with an inductance meter which are now quite cheap from China. Read Hop's #9 to try to get a weak shock.
  5. duke37

    Vintage Schematic Questions

    Just chose a resistor to give 110V across th reservoir capacitor when the valve it taking current, try 470Ω 5W. With the chassis connected to the mains, it looks like a good alternative to an electric chair.
  6. duke37

    Hartung amplifier project

    Well spotted Edd. I would suggest that a resistance check will confirm if the windings are in series bur will NOT check the phase. If you look at the diagram you will see that the primary current has to go through one winding and then the other. This is series and uses 240V. Parallel connection...
  7. duke37

    Hall effect ignition

    I agree that layout is important. Some time ago I looked at an electric fence energiser which used capacitor discharge to drive a high voltage transformer. The charger consisted of one board with another plugged into it at right angles. The electrons decided that this was too far round and took...
  8. duke37

    Hartung amplifier project

    It is not easy to get the phase of the input windings correct, they may be labelled start and finish and one start should be connected to a end leaving two wires for input. See the circuit diagram. the best way would be to use a measure of the inductance with no secondary connected. With the...
  9. duke37

    Hartung amplifier project

    You are in the UK so there will be a fuse in the mains plug. Chose a 1A fuse, this may be difficult to find, 3A and 13A are much more common. The four white wires go to two windings. These must be connected in series with the correct phase. If you are not familiar with what this means, get...
  10. duke37

    Hartung amplifier project

    As I read it, the mains input wires are white. No other wires should be connected to the mains plug other than a yellow/green earth wire to chassis. The pair of red wires should go to a bridge rectifier and nowhere else. (110V) The pair of blue wires should go to a bridge rectifier and nowhere...
  11. duke37

    Voltage source and current source on source electrode of MOSFET?

    V2 10V V ? Is M1 upside down?
  12. duke37

    Can minor fumes from old tubular lead acid batteries cause permanent damage to lungs

    You appear to be vastly overcharging the cells and the gassing is blowing acid all over the place, each cell should have a vented stopper which will catch acid droplets. Hydrogen will difuse quickly but inside the cell is a mixture of oxygen and hydrogen at the optimum concentrations for an...
  13. duke37

    Dial cord slipping

    No, but you may be able to open the collet knob with a quarter inch drill. I had trouble some time ago and used too big a hammer and could not get the knob off again.
  14. duke37

    Converting Double Insulated Light To Faux-Case Grounded

    Go for extending the internal heat sink, Use as thick a sheet as possible and cut it into offset fingers so the air can pass through from one side to the other. The plastic case will produce considerable thermal resistance but I woud not modify this. To add an external heat sink will involve...
  15. duke37

    Help with fence charger schematic

    Transformers produce AC only. If you want DC you will need to rectify the output. I have seen a fence charger with output rectifier, I do not know the effect of this, it is possibly to counter the effect of fence capacitance. A magneto produces AC. For low voltage ignition, the output is...
  16. duke37

    Help with fence charger schematic

    In theory, 10% more turns will give 10% more voltage but there will be a secondary effect of additional coil capacitance. Also, making modifications to a HV transformer may give insulation problems. 10% difference in the fence voltage will be irrelevent. You can get low voltage DC to high...
  17. duke37

    Power supply for lamp

    12V at 2A is 24W and you wnt to supply a filament lamp of 20W. All looks OK on the surface but a filament lamp has several times less rsistance when cold. I would suggest that the power supply cannot provide enough current to get the filament hot. An AC supply may be just a transformer with no...
  18. duke37

    Info for 2N3904 and 2N3906

    No,no,no Voltages relative to the emitter. The description of the action of the NPN is correct. A positive voltage on the collector will result in a current when a small positive voltage is applied to the base. With no base voltage, the transistor is OFF. The PNP uses the reverse polarity. It...
  19. duke37

    Combining 2 +12v wires in the car

    LEDs are cheap, use a separate one for each circuit.
  20. duke37

    POE 48vdc to 24-26 vdc

    I do not know the resistance of your cable, you could look this up. You can then calculate voltage drop, remember that the current has to go out and back. The LM317 will drop the voltage in a linear manner so producing heat. If you use a buck convertor, the input current will be almost half the...
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