[efoote868]

Originally Posted by Matt Krass

I was contemplating this solution today, as my team destroyed a brand new Jag today with reversed wires. The simplest way to do that would be a P-channel FET with a grounded gate, power to Drain and output from Source. A suitable (set of) FET(s) would have to be as robust and efficient as the N-channel FETs in the H-bridge, which complicates things, it could be done, but my hunch is that it wouldn't be space, power or cost effective. Perhaps, using an N-channel FET or two in parallel with a diode protected driver IC with a charge pump might work better, but its still going to waste some power to heat, and add complexity and cost.

I think overall, despite the very frustrating problem of reverse polarity burnouts (today still irks me!) it wouldn't be worth it for such a reverse polarity protection scheme, I'd rather try to educate our students better so this doesn't happen again.

Matt

Making a product like this fool-proof takes away an important $90 lesson, which can easily be split between 3-15 people. The other thing is that the lesson learned doesn't only apply to the $90 part, but potentially 1000 dollar or more parts.

When I was still in high school, one of the freshmen on the team fried the camera. If I recall correctly, that camera cost about $200. While they felt bad about it for a week, I'm certain they or anyone there never made that mistake again.