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  1. duke37

    Transformer identification

    The white wires look to be very thick and is likely to be a low output voltage. Measure the resistances between wires to determine which windings are connected. The transformer may have twin input windings which can be connected in series for 240V or in parallel for 120V. In any case running a...
  2. duke37

    Help with an inductive heating circuit!

    I may be wrong, it has been known:) The new drawing is neater but still the same. The circuit looks like a multivibrator with the diodes as feedback. Capacitors would normally be used here. One drain goes to the power supply via a choke and has no effect on the heating coils. The other drain...
  3. duke37

    Help with an inductive heating circuit!

    I do not understand your circuit, redraw it in a standard way Ferrous is not a good definition of the heated material. Stainless steel comes in two flavours, austenitic which is non or very little magnetic and ferritic which is magnetic and will heat much better. Carbon steel is ferritic and...
  4. duke37

    FM & LED shop lights

    The coax is fed from the antenna, not the receiver. The shop lights are producing interference on one frequency, this is where the propblem is. A directional antenna may help to distinguish one source from another. Chose a Yagi, two to four elements and set it up for the correct polarisation. A...
  5. duke37

    Trying to buy an underwater Infrasonic magnetostrictive transducer

    I dreamed last night and came up with a solution.:) Take a plastic pipe and fit a speaker to one end, a speaker designed for horn loading will be best. Immerse the other end of the pipe in the water and adjust the depth to resonate at the frequency you are interested in. At resonance the...
  6. duke37

    Oscilloscope Question

    Voltages are measured between two points. If you only connect to one point (the positive) then the other connection is floating and may be up to the full mains sine voltage, so masking the much smaller charger output.
  7. duke37

    Oscilloscope Question

    Battery chargers have floating output so just connect the scope to the charger output leads. No need to bother about grounding. If the rectifier is working properly and you have a load such as a low value resistance or bulb, then you should see rectified AC which will look like a chain of...
  8. duke37

    Oscilloscope Question

    A simple battery charger is not half wave, it contains a bridge rectifier which will show two half waves side by side, one from the positive half cycle and one from the negative half cycle. The waveform will have a DC component and also a AC component. If charging a battery, current will pass...
  9. duke37

    Homemade Multi-Drill

    The power supply has short circuit protection but it does not say it has a current limit, if the protection is activated, do you have to switch off to go again?
  10. duke37

    Homemade Multi-Drill

    The picture of the motor shows a plain shaft or an output gear. It does not say what you will get. The power supply has a fixed output voltage. You will need to get the right supply to give the motor speed you want. Speed will be propotionate to voltage. So long as the supply can provide more...
  11. duke37

    Homemade Multi-Drill

    For drilling wood you need speed or very sharp tools to get a good finish. Routers typically use up to 20000rpm and produce dust rather than shavings.The smaller the drill, the faster it should run. There is a best speed measured in m/s depends on the wood. Think of it working like a grass...
  12. duke37

    Volt/Amp dependent RLC band pass -> Loudspeaker expander using lightbulbs

    A solid state amplifier will have lots of negative feedback and a very low output impedance. A valve amplifier without feedback will have a high output impedance but quality amplifiers will have negative feedback to reduce distortion and this will reduce the output impedance. There is a vast...
  13. duke37

    Volt/Amp dependent RLC band pass -> Loudspeaker expander using lightbulbs

    If the amplifier has a low output impedance, then it will produce more power at the resonant frequency to light the bulb. The energy comes from the amplifier. which maintains a constant voltage. If you raise the output impedance of the amplifier, say with a 5Ω resistor, then the speaker volume...
  14. duke37

    Volt/Amp dependent RLC band pass -> Loudspeaker expander using lightbulbs

    Welcome Max If the amplifier has a low output impedance, then the speaker voltage and output will not change, just the bulb will light at the resonant frequency
  15. duke37

    Fence flasher

    @frans Please tell us the type of fencer which you have and some pictures. Fencers come in two main types, battery driven and mains driven. The battery driven fencers are rather weak and nothing other than a neon should be connected to the output. Mains driven fencers are much more powerful...
  16. duke37

    Fence flasher

    Resistors have a maximum voltage rating maybe 1kV. You may be better to use a capacitor dropper with suitable voltage rating. Older fencers used neon indicators but they went black with use.
  17. duke37

    Carpet Cleaner Circuit / Transformer

    Check there is a connection through the motor. Look for a commutator, if present, check the carbon brushes.
  18. duke37

    Back emf?

    Use a more powerful battery. Reduce the load. Some information on the battery type and load current would be helpful. Does it work?
  19. duke37

    Hi, can somebody help me with feedback circuit

    If you draw a horizontal ground line and a horizontal power line, clangers like this will be less likely. I hate lumps of 'earth' floating through the air.
  20. duke37

    Hi, can somebody help me with feedback circuit

    It will not work. Q1 has no power.
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