> The 9V battery clip is a serious source of semiconductor damage, because the
> customer ALWAYS touches the battery to the WRONG clip direction before he
> locates (by feel) the correct direction- and the damage is already done.

The gate is connected to the negative terminal through a 1 MOhm resistor to
provide some protection on it.  I don't know how good it is, though, but I
suspect pretty good.

> My standard way of doing that is to use a Schottky diode, like a 1N5818
> in series
> with the positive lead. The drop is usually less than 100mV, and
> negligible at
> 100uA. It seems to be about $0.10 USD max.

Schottky diodes can allow much more reverse current than a MOSFET will;
datasheet says 1 mA at 25 deg C.  But I suspect even 1 mA should be
tolerable.  I may experiment with that some.

Mike H.
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