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  1. KrisBlueNZ

    Stage Line 500W amp repair project

    Test with the board powered up, and measure voltage. Yes, Q11 and Q22 were MPSA92s. If the old ones measure OK out of circuit you can use them. Test them on the diode range of your meter. You should measure two diodes inside them, as in the PNP part of the second image in post #120. The correct...
  2. KrisBlueNZ

    Fireflies blinking lights

    OK, prepare yourselves for... Kris's crazy firefly suggestion, in glorious Krisometric projection :-) So the whole thing would be enapsulated in potting resin or similar. The light would come out from the front of the head section. The coil area would contain a coil internally, located...
  3. KrisBlueNZ

    Fireflies blinking lights

    OK, how about this for a crazy idea. They don't need to be very bright, do they? And they need to be weatherproof and simple to deploy? How about making them as fully enapsulated, cylindrical devices with a cylindrical coil near the surface, and coupling energy in by winding another wire...
  4. KrisBlueNZ

    Battery question

    I see. And that's not to mention the fact that often, the capacity specifications themselves are pulled directly out of the ears (or an anagram of it) of the marketing department! Thanks for the correction!
  5. KrisBlueNZ

    Does anyone know what this is?

    Yes, that's what it looks like to me as well. Is it in your gmail inbox? We don't have permission to view it. Save it to your hard drive, use the Upload a File button and upload it as an attachment to your post.
  6. KrisBlueNZ

    Designing a Time Delayed Relay

    Yeah, good point there.
  7. KrisBlueNZ

    Current limiting strategies for L298N?...

    Yes, likewise. But the overcurrent detection is a valid approach. The question is, what do you do when overcurrent is detected? Oh dear. Well, if it helps, you can tell them from me (formerly a professional electronic design engineer for 20 years) that IMO you just can't buy, or put a value on...
  8. KrisBlueNZ

    Need help on converting 0-5v signal to 0-10v signal

    Yes, if you put at least a resistor between the incoming power and the zener, and a smoothing capacitor across the zener (e.g. 470 µF 25V electrolytic), and power the op-amp at the zener. Choose the resistor to drop about 1V at the expected current. If you're not sure, as in this case, assume...
  9. KrisBlueNZ

    Designing a Time Delayed Relay

    AFAIK fuses inside mains plugs are not normal outside of the UK. They're not a bad idea, because they protect against severe damage to the mains lead, as well as failure of the equipment, whereas fuses in the equipment don't protect the cable; the switchbox fuse will blow if the cable gets...
  10. KrisBlueNZ

    Signal -> System = Oscillator

    If you can shift the data through a shift register (which requires a clock to be provided), you can see the history of the data bits as they shift through the register. Can you use that information to detect a bit sequence of 1, 1, 0? Can you work out how to increment a counter once every time...
  11. KrisBlueNZ

    Signal -> System = Oscillator

    That's not enough information. What is the data rate, in bits per second? Does the data use any framing such as start or stop bits? In other words, is it byte-asynchronous? Is there a clock provided along with the data? In other words, is it synchronous? Do the 110 patterns need to be...
  12. KrisBlueNZ

    Stage Line 500W amp repair project

    Sounds like Q6 is shot. The base and emitter terminals of a transistor have an internal diode connected between them. It is called the "base-emitter junction". A diode conducts current in one direction: when the anode (the blunt side) is positive relative to the cathode (the point and bar...
  13. KrisBlueNZ

    Transformer/Coil

    Hi there and welcome to Electronics Point :-) Can you post a schematic please, and any other information you have about the circuit. Use the "Upload a File" button to attach files to your post.
  14. KrisBlueNZ

    Thoughts on the Turing Test.....

    CSR = customer service representative? It's Turing ("TEWW-ring") not Truing. I'm surprised you didn't mention the program that recently "passed" the Turing test. It pretended to be a 13-year-old Ukranian boy called Eugene Goostman; if anyone asked it about current events or pop culture it...
  15. KrisBlueNZ

    Current limiting strategies for L298N?...

    I doubt it. No. Sorry to be unclear. More likely to cause problems. ICs aren't supposed to be powered from flimsy supply voltages. It's best to give the IC a stable supply and perform the current limiting in its output connections. They won't do you much good. Get some PTC resettable fuses...
  16. KrisBlueNZ

    3 watt LED mounting..

    If this is a test to prove the suitability of epoxy for use later, you may need to consider the matching of the two surfaces. If the surfaces you used in this test were both very flat, or happen to be deformed in the same way, the epoxy layer between them will be very thin, and this may...
  17. KrisBlueNZ

    Designing a Time Delayed Relay

    If there's a failure inside the primary of the transformer, something is going to blow, and with relatively thin tracks like you currently have, it will be those tracks, unless there's a primary fuse, which there isn't. You could thicken the tracks and leave a short section thin, so if that...
  18. KrisBlueNZ

    Word Clock circuit help

    There could be many reasons for the problem. I would start by connecting your meter across the 5V rail on the Arduino and seeing what happens to that. Also, double-check your connections to the off-board circuitry, and perhaps take a few close-up photos so we can check them too. You don't have...
  19. KrisBlueNZ

    Giday from Perth, Western Australia!

    Hi Daniel and welcome to Electronics Point :-) From Perth, the home of the brilliant and talented Tim Minchin! I hope you enjoy your time here.
  20. KrisBlueNZ

    Current limiting strategies for L298N?...

    Just some initial thoughts... Use a PTC resettable fuse in series with the load to deal with long term overloads Use a more modern H-bridge IC such as the TLE5206-2S (http://www.digikey.com/product-detail/en/TLE5206-2S/TLE5206-2S-ND/1283081) or anything from this Digi-Key product filter...
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