Electrical Engineering Terms
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

Transistor Terms

Transistor. A semiconductor device with three or more elements, Emitter, Base, Collector. A semiconductor device capable of providing power amplification. Also called a Bipolar Junction Transistor [BJT], [BJT Manufacturers]


Alpha. The emitter-to-collector current gain in a common-base circuit of a transistor.

Base: A region which lies between an emitter and collector of a transistor and into which minority carriers are injected.

Collector: A region through which a primary flow of charge carriers leaves the base.

Emitter: A region from which charge carriers that are minority carriers in the base are injected into the base.

Common Base. Grounded Base. A transistor circuit in which the base electrode is the common element to both input and output circuits. Normally the emitter is used as the input terminal and the collector is used as the output terminal. The common base configuration does not produce a phase shift between the input and output and is commonly used as a voltage amplifier.

Common Collector. Emitter Follower [shown below right]. A transistor circuit configuration in which the collector is the element common to both the input and the output circuits. The common collector configuration does not produce a phase shift between the input and output.

Common Emitter. A circuit configuration in which the emitter of a transistor is the element common to both the input and the output circuits. The common emitter configuration produces a phase shift of 180 degrees between the input and output.

Common Emitter transistor circuit
Common Emitter

Cutoff Current. The cutoff current is the measured value of dc current when a transistor is reverse biased by a voltage less than the breakdown voltage.

Bias Resistor Transistors. [BRT] The Bias Resistor Transistor houses a transistor a series Base resistor and a Emitter to Base feed-back resistor in a single surface mount plastic package. Currently only used with small signal transistors, around 100mA collector current [Ic] and surface mount Small Out-line Transistor [SOT] packages. The low power or small signal transistor is used because both the transistor and bias resistors are in the same package. The BRT style have also only been found being produced by ON Semiconductor.

Darlington. Darlington Amplifier, a double emitter follower. Two transistors connector so they operate as if they are a single transistor. A Darlington pair can be either produced using individual transistors or purchased as a single device, as in a 2N6301.

NPN Darlington Transistor Circuit Schematic

Saturation: A base current and a collector current condition resulting in a forward-biased collector junction. The condition existing in transistor in which an increase in the input signal produces no further change in the output. The operating point of a transistor at which a further increase in grid or base current no longer produces an increase in collector current.

Storage Time. An increase in the time required to turn off a transistor after the device was driven into saturation.

hfb, hfc, hfe: Small signal short circuit forward current transfer ratio (common base, common collector, common emitter)

hib, hic, hie: Small signal short circuit input impedance (common base, common collector, common emitter)

Supply Voltages
VBB: Base supply voltage
VCC: Collector supply voltage
VEE: Collector supply voltage

Terminal-to-Terminal Voltages
VBE: Base to Emitter voltage drop
VCB: Collector to Base voltage drop
VCE: Collector to Emitter voltage drop

Related topics: Derating Terms
Transistor Configurations
Transistor Packages, also sometimes called discrete package.

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