Geared DC motors can be simply put as an extension of DC Motor. The speed of the motor is counted in terms of rotation of the shaft per minute and is termed as RPM .Simple DC motors are restricted in terms of power and lack proper speed control. They can even run at speeds approximately close to 3,000 RPM which might get beyond the desired requirements of the user. However, using a geared motor can reduce down the RPM such as 150 and lower, hence providing more torque to the machine. This concept where gears reduce the speed of the vehicle but increase its torque is known as gear reduction. This Insight will explain those major as well as minor details that make the gear head and hence the geared DC motor work.
Servo Motors are DC Motors with a servo mechanism to provide a precise angular motion. Pulse width modulation (PWM) technique is used to set the angle of rotation. Generally RC servo motors have a rotation limit of 900 to 1800 but servos with high rotation angles are also available.A DC motor and the potentiometer which is used to provide feedback to the electronic circuitry. It is connected with the DC motor with the help of gear assembly. As soon as the motor starts rotating the potentiometer also starts rotating and the output of potentiometer i.e. voltage across the middle terminal changes which acts as the feedback signal to indicate the degree of rotation of the motor.