Electrical control devices

alternating current alternating voltage amplifier analogue anode anode current applied voltage armature atoms capacitance capacitor cathode causes conduction conductor connected contacts control circuit control system control winding controlled variable current passed detect detector direct current discharge electrical electromagnetic elements energy error field windings frequency full-wave germanium heat increased induced voltage input junction light liquid load circuit load current magnetic amplifier magnetic flux manipulated variable material measuring metal metal rectifiers motor N-P-N transistor negative voltage operation oscillator circuit output voltage P-N-P transistor photocell photoelectric phototransistor plates polarity positive half cycles potentiometer produced proportional pulse radiation rectifier reduced reference voltage relay resistance resistor reverse rotor saturable reactor semiconductor sensing devices sensor servomotor set point shown in Fig shows signal speed stator supply switch temperature terminals thermionic thermionic valve thermistor thyratron thyristor torque transducer transformer transistor transmitter triode triode valve tube ultrasonic voltage applied zero