AI-3
FIELD-EFFECT TRANSISTOR (FET)—A transistor consisting of a source, a gate, and a drain.
Current flow is controlled by the transverse electric field under the gate.
FIDELITY-—The faithful reproduction of a signal. The accuracy with which a system reproduces a
signal at its output that faithfully maintains the essential characteristics of the input signal.
FIXED BIAS—A constant value of bias voltage.
FORBIDDEN BAND—The energy band in an atom lying between the conduction band and the valence
band. Electrons are never found in the forbidden band but may travel back and forth through it. The
forbidden band determines whether a solid material will act as a conductor, a semiconductor, or an
insulator.
FORWARD BIAS—An external voltage that is applied to a PN junction in the conducting direction so
that the junction offers only minimum resistance to the flow of current. Conduction is by majority
current carriers (holes in P-type material; electrons in N-type material).
FREE CHARGES—Those electrons that can be moved by an externally applied voltage.
FULL-WAVE RECTIFIER—A circuit that uses both positive and negative alternations in an
alternating current to produce direct current.
FULL-WAVE VOLTAGE DOUBLER—Consists of two full-wave voltage rectifiers and is used to
reduce the output ripple frequency.
FUSED-ALLOY JUNCTION—See ALLOYED-JUNCTION.
GALENA—A crystalline form of lead sulfide used in early radio receivers.
GAMMA—The emitter-to-base current ratio in a common-collector configuration.
GERMANIUM—A grayish-white metal having semiconductor properties.
GROWN JUNCTION—A method of mixing P-type and N-type impurities into a single crystal while the
crystal is being grown.
HALF-WAVE RECTIFIER—A rectifier using only one-half of each cycle to change ac to pulsating dc.
HALF-WAVE VOLTAGE DOUBLER—Consists of two half-wave voltage rectifiers.
HOLE FLOW—In the valence band, a process of conduction in which electrons move into holes,
thereby creating other holes that appear to move toward a negative potential. (The movement of
holes is opposite the movement of electrons.)
HYBRID CIRCUIT—A circuit where passive components (resistors, capacitors) are deposited onto a
substrate made of glass, ceramic, or other insulating material. Then the active components (diodes,
transistors) are attached to the substrate and connected to the passive components on the substrate
with a very fine wire.
IGFET—Any field-effect transistor that has an insulated gate.
INDUCED CHANNEL MOSFET—A MOSFET in which there is no actual channel between the source
and the drain. This MOSFET is constructed by making the channel the same type of material as the
substrate.
