I need to use a 12v relay to control power to a project that is a
12V/20A load.

My plan, is to use an automotive 12v 30A relay. The relay's coils have
~80ohms of resistance. The relay has a builtin diode to handle the
inductive kickback when de-energizing the coil.


I plan is to feed the emitter of a 3906 from 12v, connecting the
collector to the coil, and grounding the other end of the coil.

The base of the 3906 will connect to the collector on a 4N26
optoisolator through a ~5K resistor. The emitter of the 4N26 will be
grounded.

I'll be using an AVR microprocessor to drive the LED in the 4N26.

Does this all seem reasonable? I'm new at designing things like this,
and though it is a simple circuit, I want it to be reliable and safe, so
I'll take any criticism and or suggestions you have ( about the circuit ;-)

- jim