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  1. (*steve*)

    Help Identifying MOSFET ?

    In that case you need to figure out where it came from. Hard to say. I haven't seen the specifications of the original part, I don't even know that it's an n channel MOSFET. What Vgs does it operate at? (rhetorical question)
  2. (*steve*)

    12VDC Backup supply

    And you can refer to the formula I gave previously that is correct for this instance. My recommendation was for a lower charge rate. (I went for 200 hour, @Audioguru went for about a 30 hour)
  3. (*steve*)

    LED buck drivers and reducing current

    And be careful with PWM and videography. You might end up with strobing on your recording.
  4. (*steve*)

    Help Identifying MOSFET ?

    Oh, and a TRIAC is essentially like a switch you can turn on, but can't turn off again. It turns off only when power to the load is removed. Tries are often used with AC circuits because the nature of AC (the type that comes out of your mains socket) is that it effectively turns on and off 100...
  5. (*steve*)

    Help Identifying MOSFET ?

    What you've cleaned up may have been the heatsink compound that is required to ensure a good thermal contact between the device and the heatsink. It is typically white with a consistency a bit like toothpaste when new, but it can dry out a bit and get firmer.
  6. (*steve*)

    12VDC Backup supply

    Yeah, I agree with @Audioguru if you want to do this, stick to the 9V battery. However, you seen to have completely ignored the issue if the GPS when not in standby mode. Surely the point of this battery is to provide power to the GPS to allow it to perform it's tracking function when the main...
  7. (*steve*)

    12VDC Backup supply

    Now you've removed the necessary diode. Why? And we still don't know that the unit will work when not in standby mode.
  8. (*steve*)

    12VDC Backup supply

    Have you addressed the issue if the power required by your device when not in standby mode? What is its peak power requirement and can that be supplied from your auxillary battery, and for how long?
  9. (*steve*)

    12VDC Backup supply

    That's better. Now as the resistor for a 200 hour charge rate.
  10. (*steve*)

    Filter Capacitor - Identify pins

    What is it supposed to be? (You bought it)
  11. (*steve*)

    Help Identifying MOSFET ?

    I think it is possible that the op has removed a heatsink which the PCB is clamped to. It explains the "face down" mounting of the devices. I am more concerned about the "leaking" comment. These devices have nothing to leak. If what is being seen is not heatsink compound (has this been wiped...
  12. (*steve*)

    12VDC Backup supply

    There manufacturer may say that indefinite charging at the 14 hour rate is ok, but then they're in the business of selling more cells. If you want to go down that route, the circuit I have you could also be used, just change the resistor. The resister value should be 3000h / m Where h is the...
  13. (*steve*)

    12VDC Backup supply

    There is no positive connection to the GPS in your diagram. It should connect between the diodes.
  14. (*steve*)

    Help with a Japanese Electrolytic Capacitor? prob an easy question!

    Yes, you can measure other similarly marked capacitors, but you will almost certainly have to remove them from circuit (i.e. desolder them) to do it. However, if there are other capacitors that appear similar and have other than a zero in the last position, that will lend weight (one way or the...
  15. (*steve*)

    Help with a Japanese Electrolytic Capacitor? prob an easy question!

    If your multimeter has a capacitance range, and if it goes up to 560uF, then set it to that range and place the probes on the leads of the capacitor. Read off the capacitance. Capacitors don't have the exact value marked on them. For example, 56uF could read between 50uF and 60uF.
  16. (*steve*)

    12VDC Backup supply

    In that case, why not use a normal 9V battery and the same circuit (minus the resistor). Use a good battery and replace it once a year. The problem with the circuit is that unless you disconnect the main battery you won't know if the other battery is dead.
  17. (*steve*)

    Help with a Japanese Electrolytic Capacitor? prob an easy question!

    You would need to refer to the manufacturers specifications (or measure them) to determine if 560 means 560 uF or 56 uF. 561 clearly refers to 560 uF, and if the capacitance of this range extends to 1000uF or more, then 560 probably means 56uF.
  18. (*steve*)

    Capacitor Protection Boards- How do they work?

    You've seen the method, how far along the path can you get yourself? I'm interested in how this circuit works, but I don't have time to do the reverse engineering again.
  19. (*steve*)

    Help with a Japanese Electrolytic Capacitor? prob an easy question!

    E97N and E45C are probably the series identifier for the capacitors. These capacitors are very new and are evolving at such a rate that there are more series that either of us have had hot dinners. These capacitors generally have a lower ESR and longer life (and are smaller) than more...
  20. (*steve*)

    12VDC Backup supply

    Something as simple as this should work: D1 and D2 can be 1N4001 or similar. For simplicity, a small 12V lead acid battery would be best for the auxiliary battery. R1 allows a slow trickle charge of the aux battery from the main battery to keep it topped up. A 100 ohm 2W resistor should be...
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