Practical question about servos and capacitors
October 28, 2009
I have read in many places on this site about using capacitors to reduce motor and servo noise. I am now using 0.1 uF capacitors across the leads of my motors as standard practice. I'm also using 470 uF and 0.1 uF capacitors around both sides of my voltage regulator. As yet I haven't tried applying a cap to a servo, and I have a quick question.
Where do you attach the capacitors on the servos? It is easy enough to solder caps directly to the leads of a motor, but the leads on a servo are much longer, and usually already in a nice 3-pin connector to attach to a microcontroller. I believe it is best to have the capacitors as close to the source of the noise as possible. What are some good practice ways to connect noise suppression caps to the servo?
Off the top of my head, I can think of several ways, some of them are probably really bad:
- crack open the servo case and add a small cap where the power leads come in (ick!)
- cut the servo power leads just outside the case and splice in the capacitor across the leads.
- disassemble the 3-pin connector, solder the cap to the pins, and reassemble
- run the servo leads to a PCB or protoboard, add the cap to the board, and then wire from the board to the microcontroller
So, how do you do it?