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  1. KrisBlueNZ

    What is your favourite type of component?

    A while ago I did a survey of CD40106 and CD4093 devices available from various manufacturers and found quite a wide variation in the threshold voltage ranges. The survey isn't complete but I'll post it here in case it's of interest. Interesting that the frequency formula for the Schmitt...
  2. KrisBlueNZ

    Need help with electronic circuit (Make: Electronics Experiment 8)

    OK, I thought that would work, but apparently it doesn't. I don't have any other suggestions for simple changes that would fix that problem, sorry. Do you have a transistor? For example, a 2N3904 or 2N3906? If so, I can suggest another thing to try.
  3. KrisBlueNZ

    Radio Shack score

    LOL :-) Well, that's the nature of life and death I suppose. They may not have been much use while they were alive, but in death, they release all their nutrients back into the earth, to benefit everyone else!
  4. KrisBlueNZ

    a timing circuit

    OK, the LED is either damaged/faulty, or connected the wrong way round. Try reversing it. When it's connected the right way round, the voltage from B to Z will be about 1~2V. It's possible that the LED has been damaged by being connected backwards. So even if you get the right voltage when you...
  5. KrisBlueNZ

    Schottky rectifier

    It might be worth checking the V-I graphs of the simulation models then.
  6. KrisBlueNZ

    bee venom extract device

    I agree with duke37 about using an audio amplifier driving a transformer. You can get Class D amplifiers pretty cheaply on eBay and they're very efficient and compact. With a 12V DC supply you can get nearly the full output swing, i.e. about 8V RMS, or 16V RMS if you use a BTL (bridge-tied load)...
  7. KrisBlueNZ

    Schottky rectifier

    Are you sure your simulations are exactly the same? Have a good look at the VOUT curve for the second simulation, the one using the HSMS282. The little increments I've marked with arrows, and the overall gradual curve of the green line, show that the output capacitor is not fully charged...
  8. KrisBlueNZ

    a timing circuit

    OK, that's reasonable. I've marked up the six "nodes" in the circuit. Connect your 9V battery (it doesn't matter about the other battery) and measure these DC voltages, and post the results: Cover the phototransistor e.g. with the cover from the end of a pen. Test #1. A to Z. This just checks...
  9. KrisBlueNZ

    Using $1 stereo amp in mono mode

    Ah, that's good that you knew about phasing. From memory, I think speakers are usually marked so the cone moves outwards towards the listener when you apply the voltage with the marked polarity, but you can't rely on that, especially if you're mixing manufacturers; you need to test each speaker...
  10. KrisBlueNZ

    Using $1 stereo amp in mono mode

    No, that amp won't blow up without a load! I don't know why the seller said that. Perhaps he heard that some amps need a load and decided to play it safe by telling you that. But you can put a load - say a 33Ω 1/4W resistor - across the unused output if you want. And disconnect the signal from...
  11. KrisBlueNZ

    Radio Shack score

    Nice :-) Looks like you got some good swag there!
  12. KrisBlueNZ

    Audio Amplifier distortion issue

    Yes, that's right, connect two TIP41s together like that, and connect two TIP42s together like that too; the only difference is the direction that the arrow on the emitter is pointing. Only the right hand transistor of each pair needs to be on the heatsink. Yes, keep R1 at 10k, but there's no...
  13. KrisBlueNZ

    Stage Line 500W amp repair project

    Digi-Key deal directly with manufacturers or their authorised agents. They still occasionally get caught out, but they're a much better option than eBay. Personally I would replace any component that may have been stressed, and I would always replace complementary transistors as a pair unless...
  14. KrisBlueNZ

    Audio Amplifier distortion issue

    No problem :-) Well, the other part of that circuit is OK. You wouldn't normally use TIP41 and TIP42 for the other transistors, because they're bigger and more expensive than you need for just driving the output transistors, and they have a lower gain than smaller transistors, but they will...
  15. KrisBlueNZ

    Stage Line 500W amp repair project

    Yes, they look suitable, if that's what they really are - semiconductor counterfeiting is alive and well on eBay - all you can do is hope!
  16. KrisBlueNZ

    Audio Amplifier distortion issue

    LOL but your suggestion will make a quick improvement, along with removing C1.
  17. KrisBlueNZ

    How do I make a propeller clock?

    The best place to begin, as usual, is with a Google search! https://www.google.com/search?q=make+a+propeller+clock
  18. KrisBlueNZ

    Audio Amplifier distortion issue

    That design has two major problems. First, the biasing in the output stage is wrong, and this will cause crossover distortion at low volume. Second, there is not enough current gain in the output stage, and this will cause distortion at higher volume. In other words, it will always distort...
  19. KrisBlueNZ

    Hello

    Hi Dunc and welcome to Electronics Point :-) Thanks for introducing yourself. In my experience on Electronics Point, a good introduction from a new member is the best predictor of a productive and positive relationship with other users of the site. I am (well, mostly was) a musician too -...
  20. KrisBlueNZ

    Using $1 stereo amp in mono mode

    Yep, that seems a bit odd, but hey, it's your project right? We also have several members in Australia, including two moderators. I'm about to hit the sack anyway.
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