FREQUENCY RESPONSE of a servo is the range of frequencies to which the system is able to
respond in moving the load. The ideal system can respond to whatever frequencies are present in the input
signal. Frequency response is a good way of judging servo performance. In a given servo system, good
frequency response provides maximum stability and minimum time lag.
The BANDWIDTH of a servo amplifier, ideally, must be able to accept only the range of
frequencies that represent valid servo signals.
Amplifier bandwidth is another compromise in achieving optimum servo operation.
A POTENTIOMETER is one of the simplest position sensor devices and is generally used because
of its small size, high accuracy, and output, which can be either ac or dc. Its primary disadvantages are
limited motion, limited life due to wear, and high torque required to rotate the wiper contact.
A BALANCED POTENTIOMETER in a closed-loop servo system is a voltage divider that
functions as a position sensor and produces the error voltage that is fed to the servo amplifier.