The 50A-DD Series PWM servo amplifiers are designed to drive brush type DC motors. The PWM frequency is determined by the PWM input signal. All models are fully protected against over-voltage, over-current, overheating and short circuits across motor, ground and power leads. All models interface with digital controllers that have a digital PWM output. They can also be used as a stand-alone system when using Pot 2. The 50A-DD Series amplifiers require only a single unregulated DC power supply as all logic and control voltages are generated internally. PWM input determines the output duty cycle. "Direction In" determines which side of the "H bridge" output is switching. Current limit can be reduced by Pot 1 (14 turn potentiometer), by DIP the switches and/or by an external current limiting resistor.