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  1. duke37

    Testing a diode with a 9V battery tester

    A high voltage 'diode' should pass current in one direction with some voltage drop.. In the other direction it should appear as open circuit with no current passing. The only way to test this open circuit is to provide a high voltage source such as a Megger which can give 1kV. If the 'diode'...
  2. duke37

    Magneto kill terminal...

    A transformer has a primary winding which generates a magnetic field in the iron core and this is coupled to the the secondary. The output voltage is proportional to the ratio of the turns. In this case, the magnetic field is produced by the passing magnet. The voltage is generated in the two...
  3. duke37

    400ma bipolar 12v 2 ohm drain

    Please describe what you want to do, preferably with a diagram. 12V with 2Ω gives 6A not 400mA. 12V at 400mA needs 30Ω.
  4. duke37

    Testing a diode with a 9V battery tester

    How do you know? Have you cut the gubbins open to see how many diodes are inside?
  5. duke37

    How do I boost a TV antenna amplifier to bring in weak signals?

    A masthead amplifier will be low noise and could help. Adding a noisy amplifier will make matters worse, in the days of valve TVs the input amplifier were not low noise and any boost amplifier would help. Modern TVs are much better. Get an amplifier from a reputable manufacturer, it will likely...
  6. duke37

    Testing a diode with a 9V battery tester

    If you place a diode in series with the multimeter, you should get a drop of about 0.6V so show 8.4V. A microwave rectifier will contain several diodes in series to manage the high voltage. A drop of 2.4V would indicate four diodes. If each of these can handle 1kV then the assembly would be able...
  7. duke37

    Hello,, can someone identify components in a Gallagher M4000 ?

    I have seen these components on other Gallagher fencers and have not been able to determine what they are. I bought a packet of what I thought were ceramic capacitors at a radio rally, they measured about 5pF so I do not know what they are. There used to be a website put on by a UK government...
  8. duke37

    Hello,, can someone identify components in a Gallagher M4000 ?

    So, what does it show? Are the hills alive with the sound of bagpipes?:):):)
  9. duke37

    Hello,, can someone identify components in a Gallagher M4000 ?

    If you bothered to draw a diagram and say if there is a problem, perhaps we could help. You can get a chinese instrument cheaply which can measure resistors, capacitors, inductors and transistors. I bought one and made a little plywood box to house it.
  10. duke37

    Hello,, can someone identify components in a Gallagher M4000 ?

    I do not think that the diodes and capacitors are part of the voltage multiplier, since the capacitors are directly across the diodes, not in a ladder network. In the early days of the BY100, capacitors were used to equalise the voltages across the diodes. When the RAS310AF avalanch diodes came...
  11. duke37

    Hello,, can someone identify components in a Gallagher M4000 ?

    Could you draw the circuit diagram? The neon looks in pristine condition so the unit has not been used much. They could be capacitors in a voltage doubler. There is one, bottom right with a browm tummy. Overheated resistor?
  12. duke37

    Resistor Value.

    Just below BR1.
  13. duke37

    Resistor Value.

    The mains comes in top left and is rectified by BR1 and the negative side is earthed. This will give a short circuit.
  14. duke37

    Hello, can somebody help me with an240P

    There are many ways of detecting FM signals. Look up "Wikipedeia, detectors (radio)" Detectors with dicrete components seem to have moved towards the ratio detector. Integrated circuits may be different to reduce the number of components. At one time I had a TV with a special valve (tube) which...
  15. duke37

    Hello, can somebody help me with an240P

    AudioGuru disparaged your AM receiver kit and suggested a superhet. Perhaps he could help you use this IC? Age is not too be used as a reason for incompetance, I know personally.:) I see no way of inputting tuning, it seems to be fixed tuning for TVs IFs as suggested.
  16. duke37

    What transmitter receiver setup is best for me, and how do i set them up?

    If you have ten accelerometers, how are you going to stop clashes in the data unless each accelerometer is asked to transmit. In other words they will need a receiver.
  17. duke37

    Current measurement issues

    A clamp on current meter measures current, voltage has nothing to do with it.
  18. duke37

    I buy am/fm radio kit but something i dont understand

    I used 5spice since it was on my computer and I like the way the circuit is input. It has the disadvantage that saved files cannot be read by other programs. The graph as shown was printed and scanned, hence the poor quality. The free version is limited in size and digital circuits cannot be...
  19. duke37

    Please Help!!! Need circuit board that can independently fire 22 leds.

    The only thing I know about raspberries is the jam. To get 22 different leds, you will need 22 leads or you may be able to make a matrix. 5 by 5 = 25 . To do this will need 10 leads, 5 to output positive and 5 to output negative.
  20. duke37

    Old "Kay" guitar amp question

    The 6N6 is a double valve with a zero bias output stage. No way can this be replaced by a 6L6 without circuit modification. Running a 6L6 without bias can ruin the valve, output transformer, mains transformer and rectifier. There is a description of the 6N6 on radiomuseum.org
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