Using MOSFET for a servo

[simmoinard]

Hi everyone, i'm pretty sure i miss something with my MOSFET...

I use a FQP30N06L to control a simple servo motor (4.8-6V).
I use an arduino pro mini 5V. (My servo works without the MOSFET, I tried)

When I plug :
-the DRAIN to the pin (-) of the Servo (to close my circuit),
-the GAIN to pin 9 (and 10k resistor to GND),
-the SOURCE to GND
it doesn't work if I turn ON the pin 9...

Any idea ?

[simmoinard]

Problem solved, I used a 220K resistor instead of 10K and it works.
Does anyone know how to find the good resistor in this case ?
Thank's !

[gilshultz]

Sometimes we get lucky. Post a schematic of your circuit as wired, not a frizzy thing and we can help you figure out which resistor to use.

[TomGeorge]

Hi,
It sounds like you are switching the power on and off between gnd and the servo gnd, this is not wise as there will be a current path between the arduino control pin and 5V through the servo.

It is best to remove power from the 5V side using a P-CH MOSFET.

Is there a specific reason you need to remove power from the servo?

Thanks.. Tom....