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  1. WHONOES

    Ignition Coil Driver Questions

    Regarding the Polyprop' capacitor. Not sure if a paper type would be OK. Haven't used one in over 50 years. A polyester type may be OK. As a thought, a motor start or run capacitor could work, again I haven't tried one so can't say for certain.
  2. WHONOES

    Ignition Coil Driver Questions

    You make a salient point regarding the fly back from the lower end of the transformer. Have checked with my trusty scope and it is about 50V peak which should be manageable for the IRF530.
  3. WHONOES

    Ignition Coil Driver Questions

    A 7-0-7 secondary is not mandatory. It could be 5-0-5, 6-0-6, or even 12-0-12. If it is the 12-0-12 then only one winding need be used. It could, of course, have just a single 12V secondary. It really depends on what you can easily get or may have to hand. The transformer does not have to be a...
  4. WHONOES

    Ignition Coil Driver Questions

    Yup, it would work with a single diode. The 1N4007 works fine.
  5. WHONOES

    Ignition Coil Driver Questions

    See attached a schematic for the first part of your circuit. It covers the 200V generator. I have included notes. I would suggest that you build it one bit a time starting with the oscillator. As an aside, you could use a 4093 in place of the 40106. Just join the 2 inputs together. Come back if...
  6. WHONOES

    Harmon Kardon TS7 sub amp issue

    No. Don't know the system. Just speaking from experience
  7. WHONOES

    Ignition Coil Driver Questions

    I've tried a set up with a 1.5VA 7-0-7 transformer with 2 X 115V primaries. I ran it backwards i.e. use the secondaries as the input and the primaries as the output. For the drive, I used a 40106 running as an oscillator. I use this as it gives a 50 - 50 mark space. The output drives a 2...
  8. WHONOES

    Harmon Kardon TS7 sub amp issue

    Glad you got it fixed without too much issue. Re the Bose L1. Just a thought, with out any schematic to see. It could have developed larger than allowed output offset voltage. If the amp has an offset monitor then it may be why it is switching on and off.
  9. WHONOES

    Ignition Coil Driver Questions

    So, is it a negative going pulse With Respect (WR) to 0V (ground) that you require or is the pulse positive WR to ground. Have been trying out running a small transformer backwards plus a bridge rec' and smoothing cap' and can achieve over 400V no problem. Am using a MOSfet and driving it with...
  10. WHONOES

    Ignition Coil Driver Questions

    A transformer with either a single 12V or two 6V secondaries and a single 230V or two 115V primaries. A transformer of 3VA or so will be plenty. I will have to test possible ideas here and then pass them on. I assume that you can build and test circuits. Edit: Don't buy anything yet.
  11. WHONOES

    Ignition Coil Driver Questions

    I will see what I can come up with. Edit: Do you have any small transformers to hand?
  12. WHONOES

    Harmon Kardon TS7 sub amp issue

    Another horrible power amplifier design with no discernible thermal feed back. What you are probably experiencing is thermal runaway. After repairing any broken tracks you may find and if you feel up to it, short the input connections together, place an ammeter in series with the + supply...
  13. WHONOES

    Ignition Coil Driver Questions

    Would it not be safer for you and your ECU to generate 300V from a transformer supply and switch that on and off.
  14. WHONOES

    Basic Electronic Tutors (Seattle)

    Once again I would recommend buying a copy of "The art of electronics" by Horovitz and Hill ISBN-13: 978-0521809269. Not cheap but will tell you all you need to know.
  15. WHONOES

    In what way toroidal cores are important for heavy transformer ?

    One very important advantage of Toroidal transformers is their very low (small) external field which makes them perfect for use in audio systems. I also find it easy to add extra windings to provide low current ±15V for control circuits obviating the need for another transformer.
  16. WHONOES

    Bearing found inside subwoofer! Does it go to it?

    Have built quite a few ported speakers. Never found any need for a small bearing. I think as others have intimated, little people have wondered what might happen if I just put this little thing through this hole?????
  17. WHONOES

    Technique Question

    I use enamelled copper wire, some would call it magnet wire, of the type that has solder through enamel so you don't have to scrape it off.
  18. WHONOES

    Basic Question

    I too prefer strip board. I also have a little pcb with a 16 pin IC socket on it. Each pin of the socket comes out to a PCB pin at the edge of the board. They are ideal for doing a quick birds nest circuit and easy to make changes. Have had them for the best part of 40 years. They have been used...
  19. WHONOES

    Detecting horizontal position

    Could go analogue and use a pointer.
  20. WHONOES

    Dual DC motor wiring help

    I think it would make more sense if you could produce an annotated block diagram of your proposal along with an idea of what you wish to achieve.
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