Speed control of motors (ac motors as well as dc motors) can be accomplished by using solid-state switching circuitry. In one such method, a solid-state relay is activated using a switching signal generated by a microcomputer so as to turn on and turn off the power into the motor drive circuit at high speed. The speed of the motor can be measured using a sensor such as a tachometer or optical encoder. This signal is read by the microcomputer and is used to modify the switching signal so as to correct the motor speed. Using a schematic diagram, describe the hardware needed to implement this control scheme. Explain the operation of the control system.