Description Nema 17 motor is not standard for electrical characteristics of the stepper motor. It is just faceplate and mounting holes standard to make it easier to interchange motors. Most likely you have to check from the specification that what is rated current for that motor and is it unipolar or bipolar one. Choose driver based on that. Note: Drive can always be more powerful than the motor, but you have to limit your current from the drive side. It’s also possible to use chopper drives with the less current rating, but then your motor runs underpowered. But one can definitely make assumptions on the motor size that NEMA 17 could use 1A – 2A current and NEMA 23 motor could use around 2A – 5A current. How to run a stepper motor without a microcontroller? It’s totally possible since the drive doesn’t care where it gets it’s stepping impulses. You only need some kind of source for pulses and direction. The simplest option would be to use a NE555 timer chip.