I'm building a circuit that has a number of servos on it. To eliminate servo chatter, I've seen recommendations to put in a 250uF cap (for the size servos I'm using). That much I can follow.
The question is – if I have multiple such servos, then placing multiple such capacitors seems… redundant, as the GND and VCC lines leading into them are the same line. Should I still place a capacitor per servo, as close as possible to the servo power pin? Should I just have a single larger capacitor elsewhere?
Additionally, my board needs to intermittently shut off its own power supply for a second or two, and then have enough power left to turn the supply back on (the supply has an EN pin that I can control it with to minimize the quiescent current). My idea was to use a .2F – 1F supercap to keep enough power in the circuit to last it through this shutdown, but how does that factor in the capacitor count and placement question from above?
Best Answer
I would suggest putting one capacitor for each servo and place it as close to the servo as you can. You can try different values because it depends on the application. The electronic components inside the servo will produce noise (or glitches) on the VCC line while the servo is operating, so you should place a capacitor (very close) to create a short way to GND for those noise. If you put only one capacitor for all the servos, the noise produced for one servo could reach other servo (or other components on your board) before being grounded.
Sometimes, it is possible that you need to put the capacitor on the servo wires (next to the servo). In my opinion, it would be the best.