capacitor for 12V DC gear motor

Nov 06, 2005 2 Replies

I have a 12V DC gear motor that runs at .2-1.2 amps



I do not want the motor to run if it has a supply of less than 10V from the battery



Would a capacitor be a good solution and if so, what type?



Thanks



No, you need to have some kind of cutoff. (view in fixed width font)

Vin-----o--------------o--. | G |S | o-[R3]--o---||-+ | T is a P-MOSFET | | ||-> | | | ||-+ | | | |D - [R1] | | ^ 1/2 W Diode | | | | | | '--o--- Your Motor | K | o---o--R^ TL431 [R4] | | A | | '---)---------' [R2] | | | GND-----o-------'

Use R1=10K, R2=3.3k, and R3 about 1k. R4 should be 100k.

When the voltage drops to 10V, it'll turn off.

Get the parts at radio shack, and make sure the Rds(on) of the MOSFET is less than 20 mOhms, and the Vth(gs) > -5V.

Regards, Bob Monsen God ever arithmetizes. - Gustav Jacob Jacobi

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