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  1. KrisBlueNZ

    Electronic whack-a-mole

    donkey, the schematic is there in post #20 on this thread.
  2. KrisBlueNZ

    Electronic whack-a-mole

    Thanks Chris :-) True, it wasn't trivial. I think doing it all in software, including the hardware design, would have been easier. Now I want to see it working. But I don't want to build it. That would be an even bigger waste of time!
  3. KrisBlueNZ

    MOSFETs IN SERIES

    I don't think your circuit will work. You've omitted the diode from the 12VDC supply to the MOSFET gates. I would use an individual diode from the +12V supply to each gate, and I would replace the gate-source diodes with zeners to protect the gate. Then I think it would work. But why are you...
  4. KrisBlueNZ

    Monsoon MH-500 Speakers - Need to know what IC is in U5 on board

    Can you take a clear close-up picture of the area around U5 from both sides? If it's a common part like U6 is, we might be able to identify it from the connections. I guess you've looked for the missing bit that has the markings on it? Why do you say U5 "looks like a Texas Instruments chip"?
  5. KrisBlueNZ

    Hissing in ATX power supply.

    The hissing sound could be instability in the control loop. It certainly could be caused by the output capacitors. It might be worth replacing them all, especially if the power supply is more than a few years old. Also, it could perhaps be the optocoupler or the TL431 (or similar) that drives...
  6. KrisBlueNZ

    Mysterious diode identification help!

    Have you made any progress on this? I found an old thread on another site that mentions the 458-056 transistor: http://www.candlepowerforums.com/vb/showthread.php?22438-Ultrasonic-Cleaner-power-supply-HELP! Someone in that thread also mentioned that you should never run these power supplies...
  7. KrisBlueNZ

    Electronic whack-a-mole

    Kris's CMOS Whack-a-mole design, revision 001, circuit description Whack-a-mole circuit description for revision 001 This is my design for a Whack-a-mole game implemented using CMOS MSI (medium scale integration) devices from the CD4000 series. It also uses transistors, diodes, capacitors...
  8. KrisBlueNZ

    Electronic whack-a-mole

    Kris's CMOS Whack-a-mole design, revision 001
  9. KrisBlueNZ

    Electronic whack-a-mole

    Thanks KJ6EAD. I couldn't find a playable version at Bob's Space Racers but I found a few online rip-offs. They're not exact copies of the original though. I think I'll just go with what I've been working on. I guess it's proof that something like the game can be implemented with logic ICs.
  10. KrisBlueNZ

    Electronic whack-a-mole

    Bugger! I didn't know that the game gets harder as it progresses. I guess I'll submit my design but it won't be a very accurate simulation. I can't be bothered going back to the drawing board... unless someone gives me a complete specification, and maybe not even then. This is a classic example...
  11. KrisBlueNZ

    Electronic whack-a-mole

    Well, I've nearly finished my CMOS design. I have a question, because I've never actually played whack-a-mole (I think it's mainly an American thing). Is there a random delay between the moles appearing? I know that only one mole appears at a time, and WHICH mole appears is chosen randomly...
  12. KrisBlueNZ

    How do you implement a transformer load with a transistor?

    Part of your problem may be the diode in parallel with the primary. The 1N400x series are slow diodes, designed for rectifying mains frequency and other slow applications. This will affect the circuit's behaviour at higher frequencies. Also, the presence of the diode may defeat the purpose of...
  13. KrisBlueNZ

    How does this circuit work?

    That's fantastic Doug! And thanks for the e-card, that was a nice touch. I'm sorry that you're going to have to USE the treadmill now. I guess we should've seen that one coming :-) Thanks for your kind words. You have been a pleasure to work with on this project. Best regards Kris
  14. KrisBlueNZ

    Can this be done using a JFET?

    Can you describe what you want to do? IN DETAIL? There may be an easier way to achieve what you want. We're really working in the dark without any description of what you're trying to do. We don't have ESP, you know! So far I see a failed attempt at a variable current sink, driving some kind of...
  15. KrisBlueNZ

    4047/4066 audio slicer help

    Hi Ben. You need to connect pins 1 and 13 of the 4053 to the virtual ground rail (top of C4), not the circuit's 0V rail. The way you have it, when the 4053's X switch switches to X1 and the Y switch switches to Y1, the switching network's input and output will both be connected to 0V, which is...
  16. KrisBlueNZ

    How do you implement a transformer load with a transistor?

    Stating the obvious... can you post a schematic? And details of the transformer you're using (part number, or winding details)
  17. KrisBlueNZ

    How does this circuit work?

    OK that makes sense. The TIL194 has bidirectional input. So the 0.4V you get on pin 9 of the 40106 is OK. OK, no problem. Aha! That signal must be being loaded down by something on the main board. I'm not sure what you're saying about where that signal goes. Is it the track that feeds to Q6...
  18. KrisBlueNZ

    How does this circuit work?

    OK, those voltages could be consistent if the optocoupler is an AC-input type that activates on both positive and negative voltages. In that case, a pin 9 voltage of 0.4 could be right, but pin 8 should be around 4.5V, not 3.61V. What are the markings on the optocoupler? The track from pin 8...
  19. KrisBlueNZ

    How does this circuit work?

    Bummer. Sorry about that. The 40106 looked like a very likely culprit. You should be measuring VDC. The signals are AC, but measuring the DC voltage gives us the average voltage, which should be about half the supply voltage, since the signal should have a duty cycle of about 50%, i.e. it...
  20. KrisBlueNZ

    Switching Regulator IC with Voltage Controlled Output

    Bob, that wouldn't be feasible for several reasons. The micro is busy doing serial comms and other things using several interrupt sources and DMA, and the charger output voltage needs to be fairly stable with some ripple on the input, which would require a fairly fast response. The National...
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