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  1. (*steve*)

    Greetings all

    Hi Rob, welcome to electronics point.
  2. (*steve*)

    Microphone for low frequency recording use

    A speaker in a sealed enclosure could be used. However a small vent is required unless you also want to measure barometric pressure! In any conventional microphone, if both sides of the diaphragm are open, low frequency signals are lost due to the fact that the place of the signal arriving...
  3. (*steve*)

    +15V supply shorted

    True. But in this case 20 seconds or so was enough to get the heatsink up to uncomfortably warm, and extended period got it to beyond that. Considering the other rail had a heatsink that was not noticeably above ambient, and the average voltage was 50mV, that seemed unlikely. And given that...
  4. (*steve*)

    Yusynth metaliser

    In general there would be no problem supplying some modules with +/-15V and others +/-12V. In fact, most of the modules designed for +/-12V should not be damaged by +/-15V (not a guarantee). However, a module powered by +/-15V could supply an output voltage outside +/-12V to a module powered...
  5. (*steve*)

    Panasonic blu-ray dvd assistance req'd

    What damaged it in the first place? Incorrect mains voltage, lightning strike,...?
  6. (*steve*)

    Driving a piezo buzzer: resultant tone is noisy. Why?

    Your microcontroller isn't using pwm to create something which averages out to a sine wave is it?
  7. (*steve*)

    Yusynth metaliser

    As long as they're all about converting synth modules from +/-15V to +/-12V then I see no problem. How did the first one go?
  8. (*steve*)

    +15V supply shorted

    And it all came to life with the replacement of the 7815. Here are the dead bits: And here is the other side of them (and you'll see what was hidden from me all that time...) Oh, and the new regulator runs as cool as a cucumber (makes you wonder why there's a heatsink on it actually).
  9. (*steve*)

    +15V supply shorted

    Damn! On the way somewhere I accidentally bought an LM7815.
  10. (*steve*)

    Simple Uninterrupted Power Supply Circuit

    It will probably overcharge your batteries (and/or be slow to recharge them), and we normally draw the +ve rail at the top. Is there a reason all your diodes aren't specified as schottky? Apart from that, it looks reasonable.
  11. (*steve*)

    Op amp problem ua741

    The 741 can't pull the output close to the supply rails. If you use a +/-12V supply, you will be able to get the output to 0V. This is how it is normally done. You may be able to get away with an op-amp which has rail to rail outputs, although the output may be less accurate as it approaches...
  12. (*steve*)

    +15V supply shorted

    Yeah, I promised I would leave it alone, but I suddenly thought I could use my ESR meter to probe for small resistances... Near the regulator (across that tantalum cap) I see 40 to 50mΩ. Further away I see higher resistance. And yes, it was the tantalum cap. Removing that raised the ESR to...
  13. (*steve*)

    How to build an IR-sensor from scratch?

    I think I could do it with a lock-in amplifier. But I also think it would be rather expensive :-)
  14. (*steve*)

    Does someone here know what data a Chromecast delivers to the internet?

    I have a local Plex server which can use Chromecast to play stuff on my tv. I have no idea if it works when my internet goes down. My Chromecast device uses my modem's wifi, but I guess I could just disconnect the modem from the incoming signal. However in not sure that's the question you're...
  15. (*steve*)

    How to find the circuit output

    The circuit also has a practical fault which will likely cause it to destroy transistors.
  16. (*steve*)

    +15V supply shorted

    Thanks for the information. If it is that tantalum, I bet the side I can't see has an evil grin on it. Unfortunately I'm going to be tied up all weekend (and my weekend starts now and ends Monday evening) so I'm going to have to leave this for a while. The resistance across the regulator...
  17. (*steve*)

    +15V supply shorted

    I have a power supply which generates a +/- 15V rail. The -15V is fine, while the +15V measures around 50mV. The 7815 gets very hot. I suspect it's a short :-) Unfortunately, the PSU is on a fairly large board, and I can't disconnect it from the rest of the board. I've tried my calibrated...
  18. (*steve*)

    Laptop problems help

    Gee, I could swear that the make and model you specified was one with a removable battery.
  19. (*steve*)

    Arduino Pro Mini has many faces

    Caveat Emptor
  20. (*steve*)

    Laptop problems help

    Replace the battery and the hinge
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