a basie FET question..

Well, since the source and drain are indistiguishable on a garden-variety JFET, figure it out.

And BTW... I doubt you should be playing with microprocessors, especially those dealing with recharging explosive caustic cells (not necessarily batteries!) if you don't know that a JFET gate has a diode characteristic when forward biased. +10Vgs is rather impressive; how many JFETs did you burn for that?

MOSFET on the other hand...

Tim

Please don't assume such things.

(not necessarily

Hey, do you collect them ? ;)

see this:

The N-FET will always conduct from source to drain through the body diode regardless of Vgs.

Though if I understand the 4 quadrant speed control tips from the guy at 4qd.co.uk, when the FET is on, it'll conduct forward *or* reverse currents with a Vds much less than a diode drop. Regen braking is achieved by turning on both low-side NFETs of an H-bridge until the short-circuit current through the motor L rises enough to be usefully dumped back into the supply...?

Yes.

There's almost always a substrate diode from source to drain that will turn on about -.6 volts anyhow.

John