Permeability is the measure of the ease, with which magnetic lines of force pass through a given material.


A positively charged particle with considerable mass.

Phase rotation meter

Phase rotation meter is a device used to determine the phase order of a three-phase electrical system.

Parallel Circuit

In parallel circuits, the voltage drop V across each component remains same. However, the current through each element is different.

Power Factor

Power factor is described as the ratio between active power and apparent power. Mathematically, it can be described as:


Power is the rate of doing work or the work per unit time. The unit of power is joule per second or watt.


The time duration of one complete cycle.


Certain materials retain much of their magnetism long after an initial magnetizing force has been removed. These materials or bodies are called permanent magnet.


A potentiometer or a rheostat is an instrument used to measure and compare potentials without drawing any current from the circuit.

Printed Circuit Boards

Printed Circuit Boards are made of cooper-clad, epoxy-based material that has the wiring pattern etched on it to interconnect the various components.


Phasor is a complex quantity which expresses phase and amplitude of a sinusoid.

Peak Value

The amplitude of a wave from the zero or reference axis to the maximum point in either direction.


The action of a relay as it makes designated responses to a progressive increase of input.

Pickup value

The minimum input that will cause a device to complete contact operation or similar designated action.

Positive-sequence impedance

 The quotient of that component of positive-sequence sinusoidal voltage that is due to the positive-sequence component of current, divided by the positive-sequence component of the current at the same frequency.

Positive-sequence network

 The equivalent representation of a power system constructed by using only the positive-sequence impedances of the various components.

Power angle

The phase angle between the generated voltage phasor and the terminal voltage phasor.

Power-angle characteristic

 The expression for the real power developed by a synchronous machine in terms of its generated voltage, terminal voltage, synchronous reactance, and power angle.

Power-angle curve

 The plot of the power-angle characteristic of a synchronous machine.

Power factor

The ratio of the average power in watts to the root-mean-square (RMS) volt-amperes.

Power factor angle

 The angle whose cosine is the power factor.

Power flow equations

 The system of nonlinear algebraic equations relating the phasor bus voltages to the complex power Injections into the buses of the power system.

Protective relay

 A device whose function is to detect defective lines or apparatus or other power system conditions of an abnormal or dangerous nature and to initiate an appropriate control action.

Pull-out torque

 The maximum sustained torque that the synchronous machine will develop at synchronous speed with rated voltage applied at rated frequency and with normal excitation.

Pilot Device

Some type of audio-visual indicator or a type of switching device used to control the flow of energy to a process

PLC scan

 The process the CPU goes through in order to execute a program.

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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