Engineering Dictionary
"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"

'Ca' to 'Cas', 'Cat' to 'Cg', 'Ch', 'Ci' to 'Cl', 'Cm' to 'Com',
'Com', 'Com' to 'Con', 'Con' to 'Coo', 'Cop' to 'Cq', 'Cr', 'Cs' to 'Cz'

CMOS. See Complementary Metal Oxide Semiconductor.

Coaxial Cable. Cable in which the center conductor is separated from an outer conductor by a dielectric material; used in RF transmission. A longer description may be found in the Radar section; Coaxial Cable Definition.

A high-band width cable consisting of two concentric cylindrical conductors with a common axis that is used for high-speed data communication and video signals. Manufacturers of Coax, Twinax, and Triax Cable.

Coaxial Line. A type of transmission line that contains two concentric conductors.

Coaxial Speaker. A single speaker that contains both a high frequency speaker and low frequency speaker mounted atop one another. The speaker may be a tweeter mounted atop a woofer with an internal cross-over network. Coaxial Speakers are normally found in car stereo systems as a space saving measure.

Code. Code is a combination of mark and space conditions representing symbols, figures, or letters.

CODEC. Acronym for coder-decoder. An assembly consisting of an encoder and a decoder in one piece of equipment. A circuit that converts analog signals to digital code and vice versa. An electronic device that converts analog signals, such as video and voice signals, into digital form and compresses them to conserve bandwidth on a transmission path. Manufacturers of CODEC ICs.

Code Conversion. Conversion of signals, or groups of signals, in one code into corresponding signals, or groups of signals, in another code.

Coder-Decoder. See Codec.

Code-Division Multiple Access. [CDMA] A coding scheme, used as a modulation technique, in which multiple channels are independently coded for transmission over a single wideband channel.

Coefficient of Coupling. An expression of the extent to which two inductors are coupled by magnetic lines of force. This is expressed as a decimal or percentage of maximum possible coupling and represented by the letter K.

Coherence. A definite phase relationship between two energy waves, such as transmitted frequency and reference frequency.

Coherent. Radiation on one frequency.

Coherent Oscillator. An oscillator that supplies phase references. Radar Dictionary

Coil. An inductor. An inductive device made by looping turns of wire around a core. The picture shows two different through-hole style inductors. Surface Mount Coils are also possible. Also refer to Coil manufacturers and vendors.

Leaded Coil Inductor
Thru-Hole Coils

Cold-Cathode Tube. A gas-filled electron tube that conducts without the use of filaments. Cold-cathode tubes are used as voltage regulators.

Cold Plate. A heat transfer surface cooled by forced air or other heat transfer fluid to which heat dissipating parts are mounted.

Collector. The element in a transistor that collects the current carriers. [Transistor Definitions, Manufacturers of Transistors]

Collector-Injection Modulator. The transistor equivalent of a vacuum tube plate modulator. The modulating voltage is applied to a collector circuit, shown in this example of a Collector-Injection AM Modulator.

Collet Knob. A dial or knob that uses a collet [metal compression collar] to attach to the shaft of the variable component being adjusted. Also refer to Vendors producing Knobs and Dials, and related parts.

Collinear Array. An array with all the elements in a straight line. Maximum radiation is perpendicular to the axis of the elements.

Colpitts Oscillator. An LC oscillator. An oscillator that generates a sine-wave using a feedback loop comprised of a parallel LC circuit. The feedback is taken from the connection of two series capacitors that are used to form a voltage divider and which also matches the output impedance of the 3-terminal active device. An example transistor Colpitts Oscillator is shown to the right. The Frequency of oscillation is; Fo = 1 / (2 x 3.14 x (L1 x [(C1 x C2) / (C1 + C2)]1/2).

COMB Filter. An N-Path filter response which contains a sequence of equally spaced pass-bands forming a comb, the teeth of a comb.

Combination Array. An array system that uses the characteristics of more than one array.

Combination Circuit. A series-parallel circuit. [Antenna Terms]

Combination Peaking. A technique in which a combination of peaking coils in series and parallel (shunt) with the output signal path is used to improve high-frequency response.

Combinatorial Logic. A logic subsystem that contains no memory who's output is a function of the present input. A logic circuit that only uses logic gates without the use of flip flops.

Commercial-Off-The-Shelf. [COTS] is defined as any item that can be purchased and does not need to be designed. [Detailed Definition of COTS]

Commercial Temperature Range. 0 to 70 degrees Celsius. A standard temperature range developed for equipment operating in normal 'every-day' environments. Comparison of Operational Temperature Ranges].

Common Base. The Base element of a transistor is common to both the input and output circuit, and normally grounded [Grounded -Base Configuration]. See the common Base circuit below right. Also refer to Transistor Terms.

Common-Base Detector. An amplifying detector in which detection occurs in the emitter-base junction and amplification occurs at the output of the collector junction. Also see the Transistor Envelope Detector page for an example.

Common Carrier. In the telecommunications area, the term used to describe a telephone company.

Common Collector. A transistor circuit which has the collector of the transistor grounded or common between the input and output of the transistor circuit. Also called a Grounded Collector connection when the collector is taken to ground [via a resistor]. The Base of the transistor is used as the input and the Emitter terminal is used as the output for the circuit. See Transistor Terms.

Common Collector Transistor Circuit
Common Collector

Common Drain. A configuration of a Field Effect Transistor [FET] circuit in which the Drain electrode is common to both the input and output side of the circuit, similar to a common collector circuit used with a transistor amplifier.

Common Emitter. A transistor circuit that has the Emitter pin common to both the input and output side. The input is applied to the Base of the transistor and the output is taken from the Collector of the transistor. Refer to the Colpitts Oscilltor circuit as an example, above in the right side-bar. See Transistor Terms. [Common Emitter BJT Schematics]

Common-Emitter Detector. Often used in receivers to supply detected and amplified output. The emitter-base junction acts as the detector.

Common Gate. A configuration of a Field Effect Transistor [FET] circuit in which the Gate electrode is common to both the input and output side of the circuit, similar to a common base circuit used with a transistor amplifier.

Common Identities Law. In Boolean algebra this law states that anytime the expression A(A + B) = AB or A + AB = A + B appears, it can immediately be simplified to AB without going through the process of using the distributive law, complementary law, or the law of union to simplify.

Common-Mode Interference. Interference that appears between signal leads, or the terminals of a measuring circuit, and ground.

Common-Mode Rejection Ratio. [CMRR] The ratio of the common-mode interference voltage at the input of a circuit, to the corresponding interference voltage at the output. See one possible CMRR adjustment circuit to the right. The ratio of the common-mode input voltage to the output voltage, in dB. The ratio of the differential voltage amplification to the common-mode voltage amplification.

Common-Mode Voltage. The voltage common to both input terminals of a device. In a differential amplifier, the unwanted part of the voltage between each input connection point and ground that is added to the voltage of each original signal. The voltage common to both input lines of a balanced amplifier.

Common-Mode Voltage Gain. The ratio of AC voltage, compared to ground, to the common mode input voltage.

Common Source. A configuration of a Field Effect Transistor [FET] circuit in which the Source electrode is common to both the input and output side of the circuit, similar to a common emitter circuit used with a transistor amplifier. The amplifier circuit shown is configured as a class A common-source RC-coupled FET audio amplifier.

Common Source FET Audio Amplifier
Common Source FET

The input is developed across R1, and C1 couples the input signal to the Gate. Resistor R2 is used to bias the Source, while R3 is the Drain load and develops the output signal. C3 couples the output of Q1 to the next stage. Capacitor C2 decouples the signal across R2 so that the resistor only effects the DC bias voltage and not the AC signal.

PC motherboard

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