During the eighteenth and nineteenth centuries, a great deal of research was directed toward discovering the link between electricity and magnetism. A Danish physicist, Hans Christian Oersted, discovered that a magnetic field existed around a conductor carrying an electric current. You can perform an experiment that shows the magnetic field …

Read More »## Series Circuit Applications and Troubleshooting

There are numerous applications for the principles of series circuits. This section demonstrates how to apply those principles and shows you the specific example of an airfield lighting system. In addition, troubleshooting series circuits is discussed. Applying Ohm’s Law to a Series Circuit Ohm’s law can be applied to any …

Read More »## Conductors, Insulators, and Semiconductors | Theory | Examples

All materials are classified according to their ability (or inability) to conduct as shown in Table 1. Table 1 Conductor, Insulator, and Semiconductor Characteristics A good example of a Conductor is copper. Copper wire (which is the most commonly used conductor) passes current with little opposition. A good example of …

Read More »## Ohms Law and Power in Electrical Circuits

This module will enable readers to use Ohm’s Law and electric power formulas to determine the voltage, current, resistance and power in a basic DC circuit. Objective Learner will be able to: Use Ohm’s Law to determine voltage, current, or resistance Define Energy and Power Calculate Power in a basic …

Read More »## Resistor Color Code and Resistor Tolerance Explained

As you know, a resistor is a component that is designed to provide specific amount of resistance. Resistors are classified as being either fixed or variable. A FIXED RESISTOR is one that has specific ohmic value that cannot be changed by the user. A VARIABLE RESISTOR is one that can …

Read More »## Inductor and Capacitor Basics

The ideal resistor was a useful approximation of many practical electrical devices. However, in addition to resistance, which always dissipates energy, an electric circuit may also exhibit capacitance and inductance, which act to store and release energy, in the same way that an expansion tank and flywheel, respectively, act in …

Read More »## Hybrid Parameters of Two Port Network

For analyzing circuits containing active devices such as transistors, it is more convenient to think of the input terminals of a four-terminal coupling network as a Thévenin-equivalent voltage source and the output terminals as a Norton-equivalent current source. We then describe the coupling network in terms of four hybrid parameters …

Read More »## Short-Circuit Admittance Parameters

We can represent the generalized coupling network by the π-network shown with dotted lines in Figure 1. It is simpler to work with admittances when we encounter a coupling network in the form of a π-network, which is a dual for a T-network. Although the resulting short-circuit admittance parameters (y-parameters) …

Read More »## Open-Circuit Impedance Parameters

To define the composition of a four-terminal, two-port network, we need four parameters. The test circuit of Figure 1 gives a set of parameters called the open-circuit impedance parameters (z-parameters) of the network. Figure 1 Determining open-circuit impedance parameters We start by opening the right-hand switch in Figure 1 so …

Read More »## Impedance in Series and Parallel

Resistance and impedance both represent opposition to electric current. However, resistance opposes both direct and alternating current, while the reactance component of impedance opposes only changing current. Calculations for DC circuits can be done with scalar quantities and ordinary algebra. But impedance is a phasor quantity in AC circuits, and …

Read More »## Parallel Circuit Characteristics

Parallel Circuit Definition Resistors are said to be connected in parallel when the same voltage appears across every component. With different resistance values, different currents flow through each resistor. Resistance, Inductance, and Capacitance in Parallel Circuit The characteristic of a parallel circuit is that the same voltage appears across all parallel branches. We use …

Read More »## Phasor Diagram and Phasor Algebra used in AC Circuits

Figure 1 shows a simple AC series circuit containing resistance and inductance. The sine-wave voltage source causes a sine wave of current to flow in the circuit. Since all the components are connected in series, the current in the inductance and the current in the resistance must have the same …

Read More »## Instantaneous Current in an Ideal Inductor

In the circuit of Figure 1, we assume that the inductor has negligible resistance. To satisfy Kirchhoff’s voltage law, at every instant the inductive voltage across the coil in Figure 1 must exactly equal the applied voltage. Hence, \[{{v}_{L}}=e={{E}_{m}}\sin \omega t \] Figure 1 Inductance in an ac circuit If …

Read More »## Instantaneous Current in a Capacitor

If we connect a capacitor across a sine-wave voltage source, as in Figure 1, Kirchhoff’s voltage law requires the voltage across the capacitor to be exactly the same as the applied voltage at every instant. The voltage across a capacitor can change only if the capacitor charges or discharges. Consequently, …

Read More »## Periodic Wave

Although the sine wave is by far the most important AC waveform, there are many other types of periodic waves. In electric circuits, a periodic wave is any time-varying quantity, such as voltage, current, or power that continually repeats exactly the same sequence of values with each cycle taking exactly …

Read More »