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# Basic Electrical

## RC Circuit Time Constant | Charging Discharging of Capacitor

When a discharged capacitor is suddenly connected across a DC supply, such as Es in figure 1 (a), a current immediately begins to flow. At time t1 (Figure 1 (b)), the moment the circuit is closed, the capacitor acts like a short circuit. The in-rush current iC is at its …

## Capacitor Types | Fixed and Variable Capacitors

Variable capacitors Variable capacitors are distinguished by the fact that their capacitance can be changed. Basically, there are two most common types of such capacitors named as a trimmer and rotor-stator capacitors. Rotor-Stator Capacitor The rotor-stator type of capacitor comprises two metallic plate sets. The moving plates are attached conjointly …

## Ohm’s Law Definition | Ohm’s Law Formula

Ohm’s Law Definition Ohm’s law states that the current in an electric circuit is proportional to the applied voltage and inversely proportional to its resistance. As the voltage increases in a circuit (resistance remaining constant), the current increases by the same amount. Hence, if the voltage is doubled, the current …

## Capacitive Reactance in AC Circuit

Capacitive Reactance The AC Current flow in a capacitor depends on the supply voltage and the capacitive reactance. The capacitance value and the supply frequency determine the capacitive reactance. The alternating current through a capacitor leads the capacitor terminal voltage by 90o as shown in the figure below. If a …

## Inductive Reactance in AC Circuit

Inductive Reactance Alternating current flow in an inductor depends on the applied voltage and on the inductive reactance of the inductor. The inductive reactance is proportional to the inductance value and the frequency of the alternating supply voltage. When an alternating voltage is applied to a pure inductance, the current …

## Electrical Formulas | Electrical Formulas Sheet

A Absolute Permittivity ${{\varepsilon }_{o}}=8.84*{{10}^{-12}}$ Active Power $\text{P=VICos(}\theta \text{) Watt}$ Apparent Power $\text{S=VI volt-amp}$ B C Capacitance $\text{C=}\frac{\text{ }\varepsilon {{\text{ }}_{\text{o}}}\text{ }\varepsilon {{\text{ }}_{\text{r}}}\text{A}}{\text{d}}$ Where, εo= Absolute Permittivity εr= Relative Permittivity A=Plates Area d= distance between plates Conductance $\text{Conductance}=\frac{1}{\text{Resistance}}=\frac{1}{\text{R}}$ Capacitive Reactance ${{\text{X}}_{\text{C}}}\text{=}\frac{1}{2\pi fC}$ Capacitive Susceptance ${{\text{B}}_{\text{C}}}\text{=}\frac{1}{{{\text{X}}_{\text{C}}}}$ Current in Series Circuit …

## Factors Affecting Capacitance | Dielectric Constant

There are three main factors affecting the capacitance of the capacitors that will be discussed in this tutorial in detail. The SI unit of capacitance is farad, named in honor of the English physicist and chemist Michael Faraday. The unit symbol for the farad is F. capacitance is the ability …

## Types of Resistors | Power Resistor

Resistor An element used to reduce supply voltages to some desired value or to limit current. A resistor is a small component of two leads. A wide variety of resistors is used in the electronics industry today. Carbon composition resistor The carbon composition resistor is the basic mass-produced resistor of …

## Nonlinear Resistors | Characteristics Curves of Nonlinear Devices

In most circuits, we can assume that resistance is constant in relation to current and voltage. This linear relation can be graphically shown in figure 1. Fig.1: Plot of Linear Relation between Current and Voltage For example, if 3V is applied to a certain resistor and 1A flows, then 6V …

## How to Read Resistor Color Code | Resistor Color Bands

Carbon resistors are color coded- that is, they have several color bands painted around the body near one end- to identify their ohmic values. Other types of resistors are not color-coded; instead, they have their ohmic values and, sometimes, identifying part numbers printed on them. The code has been established by …

## Resistor Power Rating | Power resistor

The physical size of a resistor is not determined by its resistance but by how much power, or heat, it can dissipate. It electric circuits, the unit of power is the watt (W), named in honor of James Watt. One watt is the power dissipated when one ampere flows under …

## Source Transformation Example Problems with Solutions

A highly valuable byproduct of Thevenin’s and Norton’s theorem is the technique of source transformation. Source transformation is based on the observation that if a Thevenin’s network and Norton’s network are both equivalent to a particular source network, then they must also equivalent to each other. This observation allows you …

In analyzing a series circuit, it becomes necessary to find voltage drop across one or more of the resistances. A simple voltage drop relationship may be obtained by referring to the following figure. The total current is given by, $I=\frac{E}{{{R}_{1}}+{{R}_{2}}+{{R}_{3}}}$ And the voltage drop are given by, ${{V}_{1}}=I{{R}_{1}}=E\frac{{{R}_{1}}}{{{R}_{1}}+{{R}_{2}}+{{R}_{3}}}~~~~\text{ }~~~\left( 1 … Read More » ## Impedance, Inductive Reactance and Capacitive Reactance Impedance is the combined resistance in the flow of current because of resistive and reactive elements in the circuit. It is measured is ohm and calculated as follows;$Z=R+jX\$ Inductive Reactance Consider a sinusoidal current to be flowing in the pure inductance as shown in the following Fig. that is …
The ratio of true power to apparent power in an AC Circuit is called the power factor and can be expressed as follows: $PF=\frac{True\text{ Power P}}{Apparent\text{ Power S}}$ It is also defined as the ratio of resistance to the impedance (series circuit): $PF=\frac{\operatorname{Resistance}\text{ R}}{\operatorname{Impedance}\text{ Z}}$ Since R/Z is the …