Good Day All.

I want to build a simple current limiter for my stepper motors.

The most simple design I have found on the internet so far is using a LM317 Adjustable Regulator.

As I am running a 36v supply this is above the limit for a standard LM317, But lucky for me there is a high voltage version.

I am going to be running 3 stepper motors in unipolor, so I am going to need 2 LM317HV's per stepper motor.

I know that using the LM317HV's with a supply voltage of 36v is going to give out alot of heat.

I am going to be mounting all 6 of the LM317HV's to a 85x90mm heatsink that has a 80mm 12v fan.

In the datasheet for the LM317HV it shows to use a 0.1uf cap on the input, but does not show anything on the output.

As said above I have found a number of current limter designs based on and around the LM317 all of them have caps on the input and output, from 0.1uf to 200uf.

I know the hole idea of the caps is to smooth out any noise to and from the LM317 but how can I work out what is going to be the best caps to use for my design?

Thanks for your time.