C

Capacitance

The property of a circuit that permits the storage of an electric charge when a difference of voltage is applied.

Current

Electric current is the rate of flow of charge in a conductor.

Current Limiting Resistor

A resistor inserted into an electric circuit to limit the current to some pre-established value.

Current Source

A two-terminal circuit element with an output current essentially independent of the voltage between its terminals and characterized by a high internal resistance.

Capacitor

A capacitor is a passive device which stores energy in an electric field and opposes a change in voltage.

Circuit

An electric circuit is a combination of various electric circuit elements to form a closed path or loop.

Capacitive Reactance

Opposition to the flow of an alternating current by the capacitance of a circuit; equal to 1/2πfC and measured in ohms.

Close Circuit

A continuous path from the voltage source through interconnecting wiring and device(s) and back to the source.

Continuous-Time System

When the time variable t takes its values from the set of real numbers, the system is said to be a continuous time system or and an analog system.

Conductance

Conductance is defined as the reciprocal of a resistance. The unit of conductance is mho or Siemens.

Closed-Loop Control System

In a closed loop control system, the controller is fed by a signal that is the difference between the reference input signal and the modified output.

Coulomb

Electric charge is a basic property of atomic particles of matter, measured in coulombs C.

Conductor

Materials with many free electrons that facilitate the passage of electric current.

Coaxial Cable

A transmission line in which one conductor is concentric to another and separated by a continuous solid dielectric spacer. 

Corona

A luminous discharge of electricity caused by ionization of the air around a conductor carrying a high potential.

Circuit breaker

An automatically operated electrical device which is designed to safeguard a circuit from damage caused by unexpected excessive electric current, generally consequent of an overloading or electric short circuit. The circuit breaker’s main purpose is to disrupt current flow after a fault in an electric system is sensed.

Circular mil

A unit of area equal to π/ 4 of a square mil (0.7854 square mil). The cross-sectional area of a circle in circular mils is therefore equal to the square of its diameter in mils.

Co-energy

A function associated with the field energy function such that the sum of the energy and co-energy functions is equal to the sum of the products of the flux linkage of a coil multiplied by the corresponding current flowing through it.

Complex power

 The product of the phasor voltage multiplied by the complex conjugate of the phasor current.

Core losses

 The power dissipated in a magnetic core subjected to a time-varying magnetizing force.

Counter emf

The effective electromotive force within the system that opposes the passage of current in a specified direction

Critical resistance

The value of field circuit resistance of a DC Shunt Generator above which the generator fails to trip.

Current divider

A parallel circuit used to split the current amongst several branches

CPU

 Central Processing Unit. A microprocessor system that contains the system memory and is the PLC’s decision-making unit.

Cycle

The positive and negative alternations of a wave.

Current Clamp or Current Probe

 A specialized piece of electrical test equipment for measuring large currents. These currents are frequently over one amp and higher.

About Ahmad Faizan

Mr. Ahmed Faizan Sheikh, M.Sc. (USA), Research Fellow (USA), a member of IEEE & CIGRE, is a Fulbright Alumnus and earned his Master’s Degree in Electrical and Power Engineering from Kansas State University, USA.

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