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  1. KrisBlueNZ

    power board - don't know what to try

    OK, I've reviewed this thread. So you've lifted one end of each of those diodes and got open circuit with the red probe to the stripe end on the highest range? That's a good sign. And you've got (or are going to get) a collection of replacement fuses, and at least one spare MOSFET? I would...
  2. KrisBlueNZ

    Help with a potentiometer/rheostat question & project

    LOL Dave :-) "Let me help you out... now, which way did you come in?"
  3. KrisBlueNZ

    power board - don't know what to try

    I find that very hard to believe. Try applying solder to the shiny areas. If the copper is really gone, yes, you can bypass it easily using wire. Wrap a short piece of wire around the component lead, solder it to the component lead, then solder each end of the wire to the nearest other...
  4. KrisBlueNZ

    Help with a potentiometer/rheostat question & project

    Hello and welcome to Electronics Point :) I haven't read your whole post, but I can tell you that you're unlikely to get any help, or even encouragement, if you want to modify the accelerator control of a diesel truck! Just Google "Toyota unintended acceleration lawsuits" to see one reason...
  5. KrisBlueNZ

    Wireless Power Transmission help!

    OK. If you're seeing peak power transfer in the calculated frequency range, you can be pretty confident that you've found the resonant frequency, unless you think that the actual inductance could be very different from the 24 µH specified.
  6. KrisBlueNZ

    power board - don't know what to try

    I'm pretty sure you've got it wrong. I can see shiny tinned copper, not dull board surface. If you're not sure, use a multimeter set to continuity range to check that it's copper all around those holes.
  7. KrisBlueNZ

    power board - don't know what to try

    I don't see anything wrong with the pad on the left. The one on the right has lost some of its solder mask, so when you solder the MOSFET back in, the solder will flow outside the original intended round area, but that doesn't matter.
  8. KrisBlueNZ

    CKP sensor design with comperator

    What power supply rail(s) do you have available? I guess you have +12V and +5V? What is the minimum frequency of the signal from the crank position sensor that you need to be able to detect?
  9. KrisBlueNZ

    power board - don't know what to try

    I can't see any damage... can you indicate it with a circle or an arrow?
  10. KrisBlueNZ

    mini ups design

    Here's a suggestion for you. http://www.google.com/search?q=UPS+schematic&tbm=isch Also: http://forum-services-review.toptenreviews.com/25-forum-posting-etiquette-tips.html http://www.makeuseof.com/tag/7-netiquette-guidelines-writing-emails-forum-posts/
  11. KrisBlueNZ

    Wireless Power Transmission help!

    OK, good. You can calculate the expected resonant frequency using fr = 1 / (2 pi sqrt(L C)). Does that frequency match the frequency you found, roughly? If not, it's possible that you've found a harmonic of the actual resonant frequency. If you look at the Fourier analysis of a square wave...
  12. KrisBlueNZ

    resistance monitor

    Cool :-)
  13. KrisBlueNZ

    Wireless Power Transmission help!

    The inductors claim a high Q, so the bandwidth of the tuned circuit formed by L1 and C2 will be quite narrow. You will probably need to adjust your drive frequency to achieve maximum power transfer to the coil. Initially you can do a one-off adjustment but in a practical circuit it might be...
  14. KrisBlueNZ

    Leslie speaker switch

    No. All you need to do is to ask a question that someone who sees it happens to know how to answer.
  15. KrisBlueNZ

    resistance monitor

    Here's a circuit that should do what you want. It's not "simple" but it will at least work cleanly and reliably. It connects to a resistance, RS, shown on the left, and holds a relay closed while the resistance is between about 5k and 10k. R1 and R2 in series form a combined resistance of...
  16. KrisBlueNZ

    Raspberry Pi

    http://lmgtfy.com/?q=what+can+i+do+with+a+raspberry+pi?
  17. KrisBlueNZ

    Connecting AC and DC grounds on breadboard

    Yes, star earthing is another option. Do a web search for information on star earthing to see when and why it is used.
  18. KrisBlueNZ

    sioscan atomic clock model#34101 power supply

    There isn't a "circuit that turns off the screen". The display turns off because most of the clock isn't working, because there's no main supply into it. The only part that's still working is the battery-backed-up section that's powered by the battery. This is designed to run for a long time on...
  19. KrisBlueNZ

    resistance monitor

    He has a two-wire cable that runs up to 10 metres to a switch with an 8k2 resistor in parallel with it. He wants a circuit to connect to the other end of the cable, which will activate a relay if the resistance it measures (between the cable conductors) is between 5k and 10k. That will only be...
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