Common-Collector Amplifier: This is an amplifier whose collector is at ac ground. The signal goes into the base and comes out of the emitter.

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

Colpitts Oscillator: One of the most widely used LC oscillators. It consists of a bipolar transistor or FET and an LC resonant circuit. You can recognize it because it has two capacitors in the tank circuit. They act as a capacitive voltage divider that produces the feedback voltage.

Collector Diode: The diode formed by the base and collector of a transistor.

Collector Cutoff Current: The small collector current that exists when the base current is zero in a CE connection. Ideally, there should be no collector current. But there is because of the minority carriers and the surface leakage current of the collector diode.

Collector: The largest part of a transistor. It is called the collector because it collects or gathers the carriers sent into the base by the emitter.

CMOS inverter: A circuit with complementary MOS transistors. The input voltage is either low or high, and the output voltage is either high or low.

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.