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Electrical Properties of Engineering Materials

Electrical properties describe how a material conducts current, stores electrical energy and responds to electric fields or temperature differences. They guide material selection for Electrical Engineering applications. Permittivity describes a material’s polarization response to an electric field, while the other main Electrical properties of engineering materials are listed below. Resistivity Resistivity, denoted by ρ, measures … Read more

Mechanical Properties of Engineering Materials

To finalize the material for an engineering product or application, is it important to understand the mechanical properties of the material. The mechanical properties of a material are those which affect the mechanical strength and ability of a material to be molded in suitable shape. Some of the typical mechanical properties of a material include: … Read more

Working Principle of Voltmeter and Types of Voltmeter

What is Voltmeter? A Voltmeter measures the potential difference between two circuit nodes. It is a measuring instrument with the SI unit volt, V. A reading is meaningful only when the meter range, input mode, bandwidth and reference node suit the signal. Working Principle of Voltmeter The working principle of a voltmeter requires connection across … Read more

Steam Dryness Fraction

What is Dryness Fraction? Steam is dry saturated when it is saturated vapour at the stated pressure, with no suspended liquid water. Wet steam is a saturated liquid-vapour mixture that may occur in a boiler or form after heat loss. The dryness fraction of the steam, also called steam quality x, is the vapour mass … Read more

Chemical Properties of Engineering Materials

Chemical properties describe how a material reacts with its environment and whether that reaction changes composition or performance. Engineers use these properties to choose compatible materials, estimate service life and select corrosion controls. This page covers four related topics: Chemical Composition The chemical composition of an engineering material states which elements or compounds are present … Read more

Physical Properties of Engineering Materials

Engineers compare material properties before choosing a material for a product, process or operating environment. The physical properties of materials can be measured without changing chemical identity. This page also includes several mechanical and manufacturing properties, whose reported values depend on the test method, temperature, direction, loading rate and material condition. Density of Materials Density … Read more

Classification of Electrical Engineering Materials

Materials used in Electrical Engineering are called Electrical Engineering materials. Engineers classify them by the property that controls an application, such as electrical conductivity, dielectric strength or magnetic response. One material can belong to more than one functional class, so final selection also considers temperature, frequency, mechanical stress, environment and cost. The figure below gives … Read more

Rotor Resistance Control of Induction Motor

A poly phase induction motor develops torque from the difference between synchronous field speed and rotor speed. Most induction motors use a squirrel-cage rotor, but external rotor-resistance control is available only on wound-rotor or slip-ring machines because their rotor terminals are accessible. In this method, the speed control of poly phase induction motor is obtained … Read more

Analysis of Exponential Fourier Series

Fourier Series at a Glance A continuous-time signal x(t) is periodic if a positive value T exists for which the following relation holds for every t:The smallest such T, when it exists, is the fundamental period. A periodic signal satisfying suitable convergence conditions, including the sufficient Dirichlet’s Conditions, can be represented by a FOURIER SERIES … Read more

Fourier Series and Fourier Transform

Time-domain and frequency-domain descriptions show different properties of the same signal. A Fourier Series and Fourier Transform are related but distinct representations. A Fourier series represents a periodic signal by discrete harmonics of its fundamental frequency. A Fourier transform represents an aperiodic continuous-time signal with a continuous frequency variable, subject to the relevant convergence framework.A … Read more