Closed-loop quantity: The value of any quantity such as the voltage gain, input impedance, and output impedance that is changed by negative feedback.

Clipper: A circuit that removes some part of a signal. Clipping may be undesirable in a linear amplifier or desirable in a circuit such as a limiter.

Class B operation: Biasing of a transistor in such a way that it conducts for only half of the ac cycle.

Class A operation: This means the transistor is conducting throughout the ac cycle without going into saturation or cutoff.

Clapp Oscillator: A series-tuned Colpitts configuration noted for its good frequency stability.

Damper or DC Restorer: A circuit for adding a dc component to an ac signal. Also known as a dc restorer.

Chopper: A JFET circuit that uses either a shunt or a series switch to convert a dc input voltage to a square-wave output.

Chebyshev Filter: A filter with extremely good selectivity. The attenuation rate is much higher than that of Butterworth filters. The main problem with this filter is the ripple in the passband.

CE Amplifier: The most widely applied amplifier configuration, in which the input signal is fed into the base terminal and the output signal is taken from the collector circuit.

CC Amplifier or Emitter follower: An amplifier configuration in which the input signal is fed into the base terminal and the output signal is taken from the emitter terminal. Also called emitter follower.

CB Amplifier: An amplifier configuration in which the input signal is fed into the emitter terminal and the output signal is taken from the collector terminal.

Cathode: The element of an electronic device that provides the flow of electron current.

Case Temperature: This is the temperature of the transistor case or package. When you pick up a transistor, you are in contact with the case. If the case is warm, you are feeling the case temperature.

Cascaded Stages: Connecting two or more stages so that the output of one stage is the input to the next.

Capacitor Input Filter: Nothing more than a capacitor across the load resistor. This type of passive filter is the most common.