Check google... last time I did this, google found me a fairly common=20
circuit with a common 3-pin voltage reference driving an P-channel FET. =20
Pretty sure it was not even 6 components.

Cheers,
-Neil.




On 11/5/2016 5:16 PM, Chris McSweeny wrote:
> A request from a friend - he's after a really simple cutoff circuit to
> disconnect an external battery when it drops below a certain voltage.
>
> The best I can come up with is an op-amp with the negative input biased
> with a zener diode and resistor (and a voltage divider on the positive
> input) to create a schmitt trigger, with the output driving a FET, a tota=
l
> of 6 components (excluding any caps, but my feeling is we could get away
> without those if necessary). Is there any simpler way to do it, or if not
> is my circuit likely to be reliable?
>
> About 100 of these circuits needed, so we're into proper small batch
> fabrication rather than hobbyist scale, and it is for a commercial
> operation my friend runs (I'm hoping there is some budget for this, and i=
t
> might even lead to other opportunities).
>
> Thanks,
>
> Chris

--=20
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