Features: Using PWM speed control technology, with high conversion efficiency, wide speed range, and stable performance. Adopting imported semiconductor chips, and had tested the voltage, current, function etc. So the circuit is stable and reliable. Overload short circuit protection and the current no more than 30 seconds. Potentiometer is used to speed up the positive and negative switch for forward, reverse, and stop. Specifications: The resistance value of a resistor: B10K Cable length: approx. 20cm/7.87'' resistor mounting hole: 8mm Voltage: DC 10V-30V( wide range) Working voltage: 12v*3A=36W/24V*3A=72W Maximum up to 120W Rated current: 3A(Maximum continuous output current) Maximum current: 4A Modulation range: 5%-95% PWM frequency: 500HZ Module size: approx.74*47*28mm/2.91*1.85*1.10'' Net weight: approx. 66g Gross weight: approx. 70g Note: DC motor speed control input is DC, can not directly connect AC current (such as the 220V AC) otherwise it will burn. The positive and negative poles of the DC power supply can not be reversed, Otherwise the governor will damage. Motor can be divided into positive and negative, when the direction of operation and expectations are inconsistent, you can change the direction of the alignment. The potentiometer knob can change the output duty cycle of the governor, thus changing the speed of the motor. Please allow 1-3mm differs due to manual measurement. _x000D_