Reverse battery protection

[Trumpkin]

I would like to use a mosfet on my next project for reverse voltage protection. What mosfet would be the best?

[Admin]

Whats the application?

Whats being protected from what?

[Trumpkin]

Whats the application?

Microcontroller.

Whats being protected from what?

An Atmega32 and L293d from me sticking the battery in the wrong way.

[airman00]

just use a Schottky diode

[ArcMan]

Although a diode would certainly do the job, it would also drop the voltage and dissipate that energy as heat - undesirable for a motor circuit.

[airman00]

it would also drop the voltage and dissipate that energy as heat

Schottky diodes have a low voltage drop

The Schottky diode (named after German physicist Walter H. Schottky; also known as hot carrier diode) is a semiconductor diode with a low forward voltage drop and a very fast switching action.

[ArcMan]

Low is relative.  A typical Schottky diode has a 0.3V drop.  My point was that that 0.3V drop does occur and it wastes energy.  This energy waste is probably no big deal for an electronics feed or a small servo, but it can add up for a motor circuit feed.  A MOSFET has a much lower voltage drop than a diode.

[Admin]

Electrical protection: use a voltage regulator with polarity protection

Mechanical protection: set the pins up so that if the bat is plugged in backwards, nothing will happen

Labeling: mark clearly what wire goes where, use colored wiring too

[gamefreak]

Labels only help when applied correctly, my team labels things backwards all the time and I seem to recall an arm project of Admins that did the same...