PN Junction Diodes and BJT Transistors: an Introduction

This article provides a brief introduction to PN junction diodes and BJT transistors. Doping Silicon: N-Type and P-Type Semiconductors PN junctions play an important role in semiconductor fabrication for integrated circuits. An undoped silicon with a valence of four has an intrinsic concentration of ${{n}_{i}}=1.1\times {{10}^{16}}\text{ }carriers/{{m}^{3}}$ at room temperature. …

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Three Phase Power Measurement in Three Phase Circuits

Different methods are utilized in order to measure three-phase power in a three-phase circuit. In this particular article, we are going to discuss the following methods in detail: One Wattmeter Method Two Wattmeters Method Three Wattmeters Method A customer of a three-phase electrical service, three-wire or four-wire, will have a …

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Single & Three Phase Grounding

The National Electrical Code (NEC) defines “ground” as  “A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth or to some conducting body that serves in place of the earth.” Single-Phase Grounding The grounding of a typical residential, single-phase service is represented in Figure …

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Protective Relaying Principles and Applications

The applications of the different types of protection systems for the protection of various types of equipment and transmission lines are described in this section. These discussions are confined to protection for the high-voltage, bulk-power system components. Generator Protection The protection system provided to the synchronous generator must be able …

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Swing Equation in Power System

Swing Equation The motion of a synchronous machine is governed by Newton’s law of rotation, which states that the product of the moment of inertia times the angular acceleration is equal to the net accelerating torque. Mathematically, this may be expressed as follows: $\begin{matrix}   J\alpha ={{T}_{a}}={{T}_{m}}-{{T}_{e}} & {} & \left( …

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Transient Stability in Power System

Power system stability refers to the ability of the various synchronous machines in the system to remain in synchronism or stay in step, with each other following a disturbance. Stability may be classified as steady-state, dynamic, or transient stability. Steady-state stability refers to the ability of the various machines to …

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Types of Protective Relays

The protective relay is the device that responds to signals from the transducers by quickly initiating or allowing a control action to be implemented in order to prevent damage to the faulted equipment and to restore service as soon as possible. The operating characteristics of the more commonly used protective …

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Power System Protection Components

power system protection components

The operation of a power system is affected by disturbances that could be due to natural occurrences such as lightning, wind, trees, animals, and human errors or accidents. These disturbances could lead to abnormal system conditions such as short circuits, overloads, and open circuits. Short circuits, which are also referred …

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Symmetrical Components in Power System

sequence components of voltages

The method of symmetrical components is used to solve power system problems involving unbalanced polyphase voltages and currents. It is analogous to the Fourier analysis of nonsinusoidal wave shapes wherein a non-sine wave is resolved into a number of sine waves of various frequencies. In symmetrical components, the unbalanced set …

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Electrical Power System Components

power system

The electrical power system can be divided into three major components: generation (G), transmission (T), and distribution (D) as shown in Fig. 1. The generating system provides the system with electric energy. Transmission and Sub-Transmission Systems The transmission and sub-transmission systems are meshed networks; that is, there is more than …

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Analog Multimeter Working Principle

Taking a reading with an analog multimeter

An analog multimeter is a meter that can measure two or more electrical properties and display the measured properties along calibrated scales using a pointer. Analog multimeter uses an electromechanical component called a D’Arsonval movement to move the pointer along the scales to display measured values when the test leads …

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