What is a Servo Motor? A servo motor comprises of mostly DC motors with feedback for position controlling. Stepper motor is also used for position controlling but without feedback. Mostly Servo Motors are DC because they provide high locking power. The above block diagram depicts the basic block diagram that most of the servo systems are based on. Microcontroller provides PWM signal to the H-Bridge which onwards drive the motor in either direction on the basis of received input PWM signal. Lets say if PWM signal of 50% duty cycle locks the motor, so increasing or decreasing PWM value will drive the motor in CW or CCW direction. The Shaft of the motor is connected to potentiometer thus changing the Vf ( Feedback Voltage) as the motor rotates. User can set the desired position of the motor using another potentio meter. This is the Set-point voltage. Microcontroller takes the difference of both the voltages i-e Feedback and Set-point and generates a PWM signal such that Motor reaches the desired position. When it does do, the difference gets zero and ultimately motor comes into locking position. This is how DC motor servo system operates. More to Follow!