This product is a DC brush motor speed controller, need a separate DC power supply to the governor/controller power supply can not be connected to AC power can not drive brushless motor.Wide voltage 7-70V high current 30A design for a wide range of applications, on-board switch with run stop brake function, adjust the potentiometer soft line can be separated, wire length 15CM.Before wiring power, please read the wiring label, the input is DC power positive and negative poles can not be engaged, the output is connected to the motor (motor) does not need to be divided into positive and negative, if the direction of operation is not right, please replace the motor of the two wires.Circuit for optimized design, duty cycle adjustment range is wide, adjust the motor smooth without bath sound No vibration, with power indication, the circuit design is stable and suitable for long time work.On the voltage or current regulation, adjust the duty cycle is in the unit time to control the on-off time, the output is a pulse, no-load with a voltmeter to measure the output voltage and input close to the motor connected to change the duty cycle added to the motor on both sides of the average voltage changes to achieve speed regulation, the voltage changes in the current of course followed by changes. The role of the current, and the current is derived from the change in voltage.