The Caps are across vmot and gnd for each stepper driver.
From the pololu driver page, [
www.pololu.com]
"Warning: This carrier board uses low-ESR ceramic capacitors, which makes it susceptible to destructive LC voltage spikes, especially when using power leads longer than a few inches. Under the right conditions, these spikes can exceed the 35 V maximum voltage rating for the A4988 and permanently damage the board, even when the motor supply voltage is as low as 12 V. One way to protect the driver from such spikes is to put a large (at least 47 µF) electrolytic capacitor across motor power (VMOT) and ground somewhere close to the board."
"LC voltage spikes" ie the coils in the in stepper motor
Edited 1 time(s). Last edit at 01/08/2016 08:02AM by Dust.