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# Electrical Circuits

## Thevenin’s Theorem | Thevenin Equivalent Circuit | Solved Examples

Suppose that the circuit of Figure 1(a) is sealed in a black box (represented by the thick line) with only the terminals A and B exposed. A high-resistance voltmeter connected across these terminals shows that the open-circuit output voltage of the circuit is 80 V. Similarly, connecting a very low …

## Nodal Analysis with Solved Examples

Nodal analysis is a circuit-analysis format that combines Kirchhoff’s current- law equations with the source transformation. Converting all voltage sources to equivalent constant-current sources allows us to standardize the way we write the Kirchhoff’s current-law equations. For nodal analysis, we consider source currents to flow into a node. If the …

## Mesh Current Analysis with Solved Problems

Mesh Current Analysis is a technique that simplifies and speeds up writing the simultaneous equations for solving various resistance networks. The format for mesh equations is straightforward, but it cannot handle some of the networks that we can solve with the loop procedure. A mesh is a closed loop that …

## Source Transformation Example Problems with Solutions

Source transformation is a circuit analysis technique in which we convert voltage source in series with resistor into a current source in parallel with the resistor and vice versa. For a given constant-voltage source, Rint in the equivalent constant-current source has the same value but appears in parallel with the ideal current source, …

## Series-Parallel Circuit: Definition & Examples | Series-Parallel Resistors

Considered as a whole, the circuit in Figure 1 is neither a series nor a parallel circuit. However, R2 and R3 are connected between the same two points in the circuit and must have the same voltage drop. Therefore these two resistors are in parallel, and we can calculate a …

## Parallel Circuit: Definition & Examples | Resistors in Parallel

Figure 1 shows two different ways of drawing a circuit diagram for the same simple parallel circuit. Circuit diagrams usually show interconnecting conductors as either horizontal or vertical lines, as in Figure 1(a). However, to illustrate the nature of a parallel circuit, we redraw the circuit diagram by combining the …

## Series Circuit: Definition & Examples | Resistors in Series

Series Circuit Definition A series circuit can be identified by the connection between components or by the current through them. For example, in the circuit of Figure 1, R1 and R2 are connected in series because no other component or branch is connected to the junction of R1 and R2. …

## Power & Efficiency: Definition, Unit, Formula, Examples

Power is the rate of doing work. The letter symbol for power is P. The watt (W) is the Si unit of power. One watt is equal to one joule per second: 1 W = 1 J/s Equation 1 shows the relationship between power and work: \[\begin{matrix}   P=\frac{W}{t} & {} …

## Linear & Nonlinear Resistor | Definition | Characteristic Curve

For most conductors, a graph of current versus voltage is a straight line, indicating a constant resistance (see Figure 1). The smaller the resistance, the steeper the slope of the graph. Definition: A resistor that maintains a constant V/I ratio is a linear resistor. As the current through a resistor …

## Parallel RLC Circuit: Analysis & Example Problems

In parallel RLC circuits the three basic components are in parallel with each other, and, therefore, all are subject to the same voltage. The current for each branch, however, depends on the impedance of the branch and can be individually determined by employing Ohm’s law. For a parallel RLC circuit, the voltage is common …

## Series RLC Circuit: Analysis & Example Problems

In a series RLC circuit, the three basic elements are in series with each other, which means that they all have the same current. The formulation covers the general case of three types of the load being present in a circuit. If any of the components is absent (usually, the inductor or …

## Capacitors in AC Circuits

When a capacitor is subject to a voltage across its terminals, it starts charging until its charge becomes at the level of the applied voltage. During the time that charging takes place a current flows in the circuit (wires connecting the capacitor to the power source). This current is due to …

## Inductors in AC Circuits

When a coil of wire (an inductor) is connected to DC electricity (Figure 1), a current is building up from zero, making a magnetic field. The wire, itself, is in that field, and therefore, a voltage is generated in it. This generated voltage is in the opposite direction of the …

## Inductors in DC Circuits

Figure 1 illustrates a simple DC circuit consisting of a resistor with which an inductor is added in series. We are interested to see what the effect of this inductor to the circuit is. The effect of an inductor in an electric circuit is always to oppose a change in the …

## Magnetism, Electromagnetism & Magnetic Materials

One of the properties of electricity is magnetism. All motors work based on this property of electricity and its effects. Magnetism Certain metals of the iron family can become magnetized if their atoms align such that this property is enhanced. This alignment can be due to contact with another magnet, …

## Analog & Digital Multimeter

A basic multimeter can measure the three basic electric values (i.e., voltage, current, and resistance), but more functions can also be included in a multimeter. Initially, there are two types of multimeters, analog and digital. A multimeter is a must-have tool for someone working with electricity and electronics. It is …

## Capacitors in DC Circuits

A capacitor acts as a storage device to electricity. The amount of storage depends on the capacity of the capacitor. We want to study what happens if a capacitor is included with resistors connected to a DC circuit.  Figure 1a is a simple DC circuit with a resistive load, to which …

## What is Electric Power | Definition, Formula & Examples

It is always the electric power in an electric circuit that determines how much energy is going to a device, a system, or a place, and how much that energy costs. A good comprehension of the relationships for electric power, unit of power measurement, and the rules that determine power is very important. …