Right capacitor vor DRV8825?


in the Wiring diagram of the DRV8825 stepper motor driver a capacitor is recommended. Do you think this one would be fine? What happens if the capacitor has mor than 47uF, lets say twice as much? And what about the Voltage? I#m using a 12 V Transformer. Is this 16V capacitor a good choice?

Until now i didn’t use a capacitor. I just tried a few different speeds, all together my 1A 4V Stepper motor ran about 20 minutes and now it doesn’t work any more. There is no noise heard, and i can move the axle of the stepper motor without any force. What do you guess is broken? The driver carrier or the motor? What is the easiest way to find out (i only had this one carrier and this one motor…)


You can check the outputs and the VREF via with a multi-meter to see if there are any signs of life in the driver, but if your setup is no longer working, I would suspect that the driver is what was damaged rather than the stepper motor.

The electrolytic capacitor shown in the minimal wiring diagram is there to suppress LC spikes which could damage the board. I recommend using a 50V electrolytic capacitor so it is not broken by the same LC spikes you are trying protect against. 47uF is the minimum recommended capacitor value, you can use a larger one if you like. Also, the capacitor you linked to is a Surface Mount (SMD) component which might be hard to connect in your setup.

If your DRV8825 is damaged, it could also have been from something other than an LC spike. If you decide to try again, you should make sure to set the current limit to something appropriate by following the instruction in the Current limiting section of the driver’s product page.


Thank you for your explanation.
I have 0.5 V on the Rev Pin, for a 1A motor, sou it must be ok?
I still can measure this value on the rev pin. So maybe the board still is ok? How do i have to measure the voltage on the coils? Can i connect my v-meter to A1 and A2? I have no voltage here, while my stepper motor is connected and gets a signal from the orangutan-program.

Did you originally set VREF to 0.5V? If that is the case, that voltage staying the same is a good sign. In your first post you said that you could move the output shaft of your stepper motor without any force. Was the system powered when you tried this? Also, with the stepper motor disconnected, can you set your system up to step very slowly (maybe once a second or slower) and probe the A1 and A2 outputs with a multi-meter?