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  1. Tha fios agaibh

    latching pushbutton help

    Just use normally closed contact(s) to break relay(s) You could wire all the nc contacts in series, so any button pressed would break the relay coils.
  2. Tha fios agaibh

    Hi everyone! Can i ask why is there a diode here?

    People commenting on that site, can't seem to get it to work. Good call duke37.
  3. Tha fios agaibh

    FW rectifier - can't measure DC

    I can see this short circuit burning out diodes in the bridge, but why would the led burn out?
  4. Tha fios agaibh

    back into electronics as a hobby

    Well put Mick. Your fascination of electronics should make it fun to learn. Your programming experience will make learning microcontrollers, a walk in the park. John
  5. Tha fios agaibh

    Microphone inside car.

    In hindsight, perhaps I could have asked better questions. But, Martin has a valid point. In electronics things must be done methodically. When quick assumptions are made, mistakes are made. People here are great to volunteer their time and knowledge, but the onus is on the op to give...
  6. Tha fios agaibh

    Microphone inside car.

    That's why I suggested to use headphones directly from mic/preamp circuit. Anyway, you can say you gave it a shot. "A mans got to know his limitations" Clint Eastwood as Dirty Harry
  7. Tha fios agaibh

    LDO gets hot when using a relay module?

    Sorry, I didn't catch that at first. So we know coil needs 85ma to operate. Say for instance a 9v source was used directly, would we use a 36 ohm dropping resistor? 36r+70r (coil)=106ohms X .085=9v Or would it be 59 ohms calculated for the coil, making it a 47 ohm resistor? Sorry, I don't want...
  8. Tha fios agaibh

    LDO gets hot when using a relay module?

    So how was the relay working if it was only going thru signal and ground?
  9. Tha fios agaibh

    LDO gets hot when using a relay module?

    Nice find. I'm wondering why this site says 85ma instead of 71ma
  10. Tha fios agaibh

    LDO gets hot when using a relay module?

    Thanks Dave, I stand corrected.
  11. Tha fios agaibh

    LDO gets hot when using a relay module?

    My post hinged upon the fact that the ldo and relay were properly selected. Current is always the same in a series circuit. That is, at all points in the circuit. By adding a resistor, it limits the amount of current in the entire circuit (ldo included). So the resistor would help limit current...
  12. Tha fios agaibh

    Strange PSU Problem

    The good news is, you have other power supplies to use as a reference. I would put a light load (of the same resistance) on both 5v outputs, and compare voltage points from the output backwards.
  13. Tha fios agaibh

    What???

    English is tough to learn, but the Chinese do not seem to care how ridiculous they look. Their documentation usually looks like something my 6yr old would do. Reading Chinese manuals is a last resort for me.
  14. Tha fios agaibh

    LDO gets hot when using a relay module?

    ...Or find a 9vdc relay. What is the 3rd lead to the coil?
  15. Tha fios agaibh

    Strange PSU Problem

    Good idea for open caps but not if their shorted. I'm also wondering if by paralleling another cap to the underside of a good one, the double capacitance could result in blowing up something downstream. ?
  16. Tha fios agaibh

    LDO gets hot when using a relay module?

    I think you need to limit the current into the relay so devide 5v by the required coil current to get resistor value and put it in series between ldo and relay coil. Also add a blocking diode parallel with coil to mitigate spikes.
  17. Tha fios agaibh

    Modular house - intercoms won't work from front to back.

    In single phase (split phase) most 240v loads do not need balancing because they draw the same on each leg, but 120v loads do because the loading will vary so much. Also, the way loads are calculated has a lot more considerations besides the amperage. So naturally you want the amperage as even...
  18. Tha fios agaibh

    Strange PSU Problem

    Have you checked for any cracks on tracers, or bad solder joints?
  19. Tha fios agaibh

    Modular house - intercoms won't work from front to back.

    I don't remember any one suggesting the op do any work themselves. As a licensed Master Electrician, I can say exactly how loads are calculated and balanced, and it has nothing to do with points here in USA. Extension cords are for temporary use only, using extension cords as a substitute for...
  20. Tha fios agaibh

    Modular house - intercoms won't work from front to back.

    No offense, but you do not know what your talking about.
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