4. 5V, GND The motherboard comes with a 5V power supply (external power supply can be provided, the current does not exceed 10mA) 3. For forward and reverse rotation control, the motor needs to stop rotating and then perform forward and reverse operation. It is strictly forbidden to change direction during the rotation of the motor, which cause damage to the circuit board. In addition, after removing the short-circuit cap, the steering switch can be connected externally for operation. 1. When the external PWM signal is input, the amplitude is 5V, and the recommended PWM frequency is 1K-10KHz. 2. For analog input, you can use the on-board 5V, GND external potentiometer (resistance 10K-100Kohm) to adjust the speed, or you can input (0-5V) analog externally, but it needs to be connected to the GND on the board. 5. Speed ​​pulse signal output, the amplitude is 5V, each pulse represents one revolution of the motor.