A4988

The standard stepper driver on 3D printer control boards and small CNC machines. It fits a socket on a RAMPS or CNC shield and drives one bipolar stepper with microstepping selected by jumpers, giving smoother, quieter motion than full steps alone. The critical setup step is the small potentiometer that sets current limit: too low and the motor skips steps, too high and it overheats. Set it with a multimeter before running, and never plug or unplug a motor while the driver is powered — that kills A4988s more often than anything else. Drops into standard RAMPS and CNC shield sockets; Microstepping to 1/16 for smooth quiet motion; Adjustable current limit for different motors; Built-in over-temperature and short-circuit protection