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  1. Alec_t

    Advice re inductor on motor neutral

    ..... which is precisely what an NTC thermistor, such as one of these, would do.
  2. Alec_t

    Advice re inductor on motor neutral

    Have you considered using an NTC surge-limiter thermistor?
  3. Alec_t

    Capacitor as backup to 12v train camera system power

    The TS hasn't said if his 'unique' setup track supply is AC, but if the regulator input dips below the voltage of the proposed battery then the simple diode-OR arrangement I suggested in post #8 would need to be replaced with a more complex one to prevent continuous pulsed discharge of the battery.
  4. Alec_t

    Replacement Optical Isolator

    In the original circuit, is the opto-isolator being used simply for switching something on/off, or is the CdS cell at its output being used as a variable resistor for some analogue function?
  5. Alec_t

    Capacitor as backup to 12v train camera system power

    A battery similar to one of these should suit. If fully charged before installation, a trickle charge from track power would probably suffice to keep it topped up. Is that the AC RMS voltage?
  6. Alec_t

    Capacitor as backup to 12v train camera system power

    What gauge railway? This will limit battery size (hence possibly battery type).
  7. Alec_t

    Capacitor as backup to 12v train camera system power

    Do you have a Lipo charger which will accept a 12-15V input? For disconnecting the battery a power MOSFET would be more compact than a relay.
  8. Alec_t

    Bass Guitar Amplifier Build - help and guide.

    There are several ways to do that, using a simple SPST switch in the pre-amp. For example, the switch could disconnect the ALC's FET drain, or could disconnect the ALC input from the speaker (though you might need to take precautions to avoid switch-click 'thumps' if you connect/disconnect the...
  9. Alec_t

    Capacitor as backup to 12v train camera system power

    Or not. The capacitance is advertised as '783333 uF'. Not only is that unbelievably precise, but even if true it is also about half what is needed if the current draw is actually 2.5A. Edit: Rather than a cap, a 3S lithium battery pack might be a better bet. That would require a proper charger...
  10. Alec_t

    Capacitor as backup to 12v train camera system power

    Welcome to EP! To calculate the capacitor value you need to know : 1) How much current the transmitter draws, 2) How much current the GoPro draws, 3) How low the '12V' input to the 5V regulator (stepdown) can go before the 5V drops unacceptably. My guess is that you'll need a pretty hefty...
  11. Alec_t

    Charging AA Li-ion batteries

    Welcome to EP! Charging/discharging lithium batteries is dangerous, possibly causing fire or explosion if not done properly, so is best done using a dedicated commercial charger. Have you read this article?
  12. Alec_t

    Can a low side driver control three N-type MOSFETs connected in series?

    That is inconsistent. The common 12VDC implies the 4 drains are connected together; which is not a totem arrangement. 12V relative to what? Are the FET sources floating? Have you actually breadboarded the arrangement? If not, why not? It would be quicker than posting questions on a forum. If...
  13. Alec_t

    Can a low side driver control three N-type MOSFETs connected in series?

    How can they all be connected to 12VDC if they are stacked in a totem-pole configuration? Post a sketch of the arrangement. Have you actually breadboarded the arrangement?
  14. Alec_t

    Can a low side driver control three N-type MOSFETs connected in series?

    Hardly surprising when we can only guess at what you are trying to do and why :rolleyes:. Given that your project "has been privately financed for over 10 years now, and we have exceedingly mega-deep financial pockets", can't you afford the components to simply breadboard the circuit to find...
  15. Alec_t

    Ring doorbell mains power

    Scotty, this thread died over a year ago. Welcome to EP!
  16. Alec_t

    Water Motors

    Now that's what you need for your collection :D. Sorry to hear about your workshop.
  17. Alec_t

    Need a simple adjustable device to lower signal voltage?

    Judging by this article it doesn't look as though the signal source impedance is critical.
  18. Alec_t

    Need a simple adjustable device to lower signal voltage?

    Does it need to be a low source impedance? From my limited reading on O2 sensors they seem to have a ~10k resistance when the mixture is rich and a ~20k resistance when the mixture is lean, albeit their heaters are ~10Ω.
  19. Alec_t

    Need a simple adjustable device to lower signal voltage?

    Offsetting the O2 sensor output will change the average value from the 'normal' one, so it wouldn't be surprising if the ECU flagged the difference as being due to a faulty sensor and set an error code. This would be stored and detectable at the next official emissions test, even if it didn't...
  20. Alec_t

    Power supply for an in-flight entertainment system

    I'm surprised those specs don't set out all the connector parameters.
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