A voltaic cell consists basically of two different metal plates immersed in an acid solution. The action of the acid removes electrons from one plate and accumulates them on the other plate. In this way, a potential difference is produced between the two plates, and a current can be made …

Read More »## Uses for Electromagnets

Electromagnets can be made much more powerful than permanent magnets. In addition, the strength of the electromagnet can be easily controlled from zero to maximum by controlling the current flowing through the coil. For these reasons, electromagnets have many more practical applications than do permanent magnets. Crane Electromagnets One of …

Read More »## Magnetic Field around a Current-Carrying Conductor

Whenever electrons flow through a conductor, a magnetic field is created around the conductor. This important relationship between electricity and magnetism is known as electromagnetism, or the magnetic effect of current. When DC current flows, the magnetic field will act in one direction, as illustrated in Figure 1. AC current flow will produce …

Read More »## Electrical Units and Metric Prefixes

Metric Prefixes Most often measurements made on electric circuits are that of current, voltage, resistance, and power. The base units—ampere, volt, ohm, and watts—are the values most commonly used to measure them. Table 1 lists these basic electrical quantities and the symbols that identify them. Table 1: Electrical Units, Symbols, and Definition …

Read More »## Sources of Electromotive Force (EMF)

Current Electricity Current electricity is defined as an electric charge in motion. Current flow consists of a flow of negative electron charges from atom to atom, as illustrated in Figure 1. Figure 1 Current electricity. The external force that causes the electron flow is called the electromotive force (emf) or voltage which is supplied by …

Read More »## How Does Static Electricity Work?

Static electricity is the accumulation of electric charges on the surface of a material, usually an insulator or nonconductor of electricity. The term static means standing still or at rest, and static electricity refers to an electric charge at rest. The result of this buildup of static electricity is that objects may …

Read More »## Average and RMS Value of Alternating Current and Voltage

Direct current flows in only one direction. Alternating current changes its direction of flow at times in the circuit. In DC, the source voltage does not change its polarity. In AC, the source voltage changes its polarity between positive and negative. Figure 1 shows the magnitude and polarity of an …

Read More »## Electrodynamometer Type Wattmeter Working Principle

Power in an electric circuit is equal to the product of the voltage and the current. To devise a meter that measures watts, a movement similar to the D’Arsonval movement can be used. The permanent magnetic field found in the D’Arsonval movement, however, is replaced with coils from an electromagnet. …

Read More »## Electric Current, Voltage, and Resistance Overview | Three Basic Electrical Quantities

Electric Current, voltage, and resistance are three of the fundamental electrical properties. Stated simply, • current: is the directed flow of charge through a conductor. • Voltage: is the force that generates the current. • Resistance: is an opposition to current that is provided by the material, component, or circuit. …

Read More »## Electrical Components and Symbols

Electrical and electronic systems contain circuits. Loosely defined, a Circuit is a group of components that performs a specific function. The function performed by a given circuit depends on the components used and how they are connected together. Nearly all circuits, no matter how complex, are made up of the …

Read More »## Resistor Types and Color Code

One of the most common components encountered in the study of electronics is the resistor. The resistor is used to create desirable voltage drops and limit current values in electronic circuitry. Figure 1 shows several molded composition, fixed resistors. They are manufactured in many sizes and shapes. The schematic symbol …

Read More »## Electrical Circuit Devices

There are several common circuit devices that are present in most electrical and electronic circuits. They provide a means of controlling electron flow through the conductor paths and provide for safe operation of circuits. The three important items discussed here are switches, connectors, and circuit protection devices. Switches Switches are …

Read More »## Low Pass and High Pass Filter Bode Plot

Frequency response plots of linear systems are often displayed in the form of logarithmic plots, called Bode plots after the mathematician Hendrik W. Bode, where the horizontal axis represents frequency on a logarithmic scale (base 10) and the vertical axis represents either the amplitude or phase of the frequency response …

Read More »## Band Pass Filter Frequency Response

Using the same principles and procedures in the case of low and high pass filters, it is possible to derive a band pass filter frequency response for particular types of circuits. Such a filter passes the input to the output at frequencies within a certain range. The analysis of a …

Read More »## Low Pass and High Pass Filter Frequency Response

There are many practical applications that involve filters of one kind or another. Modern sunglasses filter out eye-damaging ultraviolet radiation and reduce the intensity of sunlight reaching the eyes. The suspension system of an automobile filters out road noise and reduces the impact of potholes on passengers. An analogous concept …

Read More »## Fourier Series

The aim of this article is to introduce the concept of frequency domain analysis of signals, and specifically the Fourier series. Later in this article, we explain how it is possible to represent periodic signals by means of the superposition of various sinusoidal signals of different amplitude, phase, and frequency. …

Read More »## Second Order System Transient Response

In general, a second-order circuit has two irreducible storage elements: two capacitors, two inductors, or one capacitor and one inductor. The latter case is the most important in terms of new fundamentals; however, the important aspects of all second-order system responses are discussed in this section. Since second-order circuits have …

Read More »## First Order System Transient Response

First-order systems are important in all engineering disciplines and occur frequently in nature. Such systems are characterized by a single state variable, where the system energy is proportional to the square of the state variable. That energy is dissipated by the system such that the rate of change of the …

Read More »## Maximum Power Transfer Theorem

Maximum Power Transfer Theorem Definition Maximum power transfer theorem states that maximum power output is obtained when the load resistance Ro is equal to Thevenin resistance RT as seen from load Terminals. The reduction of any linear resistive circuit to its Thevenin or Norton equivalent form is a very convenient conceptualization, …

Read More »## Superposition Theorem

The principle of superposition is a valid and frequently used, analytic tool for any linear circuit. It is also a powerful conceptual aid for understanding the behavior of circuits with multiple sources. For any linear circuit, the principle of superposition states that each independent source contributes to each voltage and …

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