The stepper motor with a rated voltage of 5V cannot be directly powered by 12V. After some method changes, 12V power supply can be achieved, the method is as follows: 1, add 5V voltage regulator circuit, using DC-DC buck chip, three-end regulator (including current expansion circuit), series voltage regulator circuit, etc., you can convert 12V power into 5V use. 2, adjust the pulse width, the stepper motor is pulsed to work, the duty cycle can adjust the average voltage, if the controller is programmable, directly through the program to change the width of the original pulse, if the controller is hardware and integrated circuit, it can not be changed. 3, if the load is stable (current is stable), direct series resistance voltage reduction; If the load is unstable, multiple diodes with comparable voltage drops can also be depressurized in series.