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  1. (*steve*)

    12VDC Backup supply

    The problem will be charging it. I bet you have good cell coverage where you are. Try fitting the module in the door and take it to a location with marginal cell coverage to get a closer to worst case estimate.
  2. (*steve*)

    Equivalent Power mosfet in HF tube welding machine

    What about these? https://www.digikey.com/product-detail/en/microsemi-corporation/APT41F100J/APT41F100J-ND/1494596 https://www.digikey.com/product-detail/en/ixys/IXFN38N100P/IXFN38N100P-ND/1995013 https://www.digikey.com/product-detail/en/ixys/IXFN44N100Q3/IXFN44N100Q3-ND/2773901...
  3. (*steve*)

    voltage regulator at 4.3V and 0.7V from 5V input that can handle inputs up to +-12V

    That's because it is a current sink, not a current source. Connecting a 4.3V zener to each supply rail might do the trick, but there won't be any current limit.
  4. (*steve*)

    12VDC Backup supply

    What chemistry is the battery?
  5. (*steve*)

    voltage regulator at 4.3V and 0.7V from 5V input that can handle inputs up to +-12V

    The +0.7V is a source, the +4.3 is a sink. I think they are just logic outputs from the chip. My rationale is that one of these lines is connected to the output of a logic gate.
  6. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    I meant without your fingers touching the metal parts. The metal parts of the probe need to touch the metal wires extending from the resistor, one probe on each end. If you have to, you can use your fingers to hold the metal part of the probe to a wire, but only on one end of the resistor...
  7. (*steve*)

    What exactly is making this beep noise?

    A very brief, shaky, blurry video shot in darkness is everything we need.
  8. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    Do it again without touching the metal parts of the probes or the leads of the resistor.
  9. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    Were you touching the metal parts of the probes or the wires when making the measurement?
  10. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    Unfortunately the 5 band resistor makes sense reading it either way around. Do any bands look wider than the others? Do you have a multimeter?
  11. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    Brown is 1%. It's a pity the op removed the other pictures. The other resistor was 2%. But I'd measure it in any case. Also the brown band looks wider, and 1.4 is a standard E48 value.
  12. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    12pF ceramic cap, and maybe a 15k resistor. I'd measure the resistor with a multimeter though. It's possible to read it the other way around, although I'm pretty sure it's what I suggest.
  13. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    Come on! Answer the question.
  14. (*steve*)

    LEDs 12 Volts?

    My guess is that they probably run from 12V and draw about 300mA in total. Try a lower voltage first and measure the current.
  15. (*steve*)

    Need Help Identify a Capacitor and a Resistor

    The first image is a diode (the glass thing) and a capacitor. Possible 12pF capacitor ±20% tolerance. My guess would be 50V or higher voltage rating. The next image is 2 diodes of some type and 2 resistors. The resistors look to be 1/2 W and 1/4W (or maybe 1/4W and 1/8W) assuming a normal...
  16. (*steve*)

    12VDC Backup supply

    A larger battery, possibly something like the one I suggested earlier.
  17. (*steve*)

    12VDC Backup supply

    You have based everything on the GPS being in standby. The 9V battery will cope with that. But what happens when it comes out of standby to report (via GSM?) The location of your vehicle? This has nothing to do with the resistor, and a lot to do with the battery.
  18. (*steve*)

    Popping sound when switching microphone with relay

    Does your microphone use phantom power? If there is a DC path through the microphone it is quite possible that current flows through the microphone to charge the input capacitor. When disconnected the charge slowly leaks away (no click) but when it is reconnected a pile of current flows (click).
  19. (*steve*)

    12VDC Backup supply

    That's fine, as long as you don't need the GPS to actually operate. I'd use a much higher value resistor.
  20. (*steve*)

    LED buck drivers and reducing current

    To determine the required resistor, calculate the approximate voltage across the LED string (don't have multiple in parallel). Then divide this voltage by the current you want to bypass the LEDs. Let's say the LED voltage is about 27 volts and the current you want to bypass is 100mA. The...
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