Resistance Resistance is defined as the measure of opposition to the motion of electrons due to their continuous collisions, with the atoms of the conductor. The unit of resistance is ohm. Let’s consider the conductor of cross-sectional area A and of length L as given below: The resistance of this …

Read More »## AC Energy Meter Working Principle

Energy is the product of power and time and is measured in watt-seconds or Joule. Since the voltage and current in a DC circuit are constant values, the energy is easily computed from a measurement of power and time, $W=Pt~~~~~~~~~~Joule$ Where W is in watt-seconds or Joules, P in watts …

Read More »## Capacitors in Series and Capacitors in Parallel

A capacitor is a passive device which stores energy in an electric field and opposes the change in voltage. An electric field can be created by placing two conducting plates in parallel and having one plate more positive than other as shown in fig. The material between two plates is …

Read More »## Difference Between Diamagnetism, Paramagnetism, and Ferromagnetism

In order to classify materials as magnetic or non-magnetic, it must be determined whether or not forces act on the material when a material is placed in a magnetic field. If a bar of any given material is suspended in a magnetic field, it will either turn at a right …

Read More »## Power Measurement In a Three-Phase System using Wattmeter

Wattmeter is an instrument, used to measure power in a circuit using current and voltage of the circuit. The wattmeter is essentially an electrodynamic mechanism, in which the stationary and movable coils separately measure the current and voltage of the circuit, as shown in Fig. The stationary coil is designed …

Read More »## RL Series Circuit Analysis

When a resistive-inductive (RL) series circuit has its supply voltage switched on, the inductance produces an initial maximum level of counter-emf that gradually falls to zero. The circuit current is zero initially and grows gradually to its maximum level. The behavior of an RL series circuit is most easily understood …

Read More »## Magnetic lines of Force | Magnetic Field

When current flows in a wire, it creates a magnetic effect around the wire which is called magnetic field. The magnetic field is specified by a direction as well as a magnitude. The following figure shows a magnetic field, of a bar magnet, by field lines that originate from the …

Read More »## Voltmeter-Definition and Working Principle

A voltmeter is a basic device used for the measurement of electric potential or voltage, in volts. As discussed in ammeter section, any basic meter mechanism has a voltage Vm across its terminals when a full-scale current Im, flows through the meter. It follows that basic meter mechanism can be calibrated …

Read More »## Permanent Magnetism Definition | Induced Magnetism Definition

Some materials are inherently magnetic (Natural Magnets). Other materials, such as Iron, are not inherently magnetic but can become magnetized if placed into a strong magnetic field. Some of these materials which do not start as magnets will retain much of their magnetism long after an initial magnetizing force has …

Read More »## Inductors in Series and Parallel | Energy Stored in Inductor

When a conductor has current through it, it becomes surrounded by an electromagnetic field. This field leads to a property known as inductance (L), which opposes any change in the current. Inductors are components that are designed to have this property. In this module, we will discuss the basic construction of …

Read More »## Magnetism

Magnetism is a property associated with materials that attract iron and iron alloys. The science of magnetism probably began with early Greeks. From that time to the present many recognized the physical effects of magnetism, yet until this century, no one understood why certain materials were a magnet. Presently it …

Read More »## Ammeter- Definition and Working Principle

An Ammeter is a device used for the measurement of current in amperes. When the current in a circuit is substantially less than an ampere, its value is determined by the use of a milliammeter or micro-ammeter, which measures full-scale currents in milli-amperes or microamperes, respectively. The symbol for the ammeter …

Read More »## Mutual Inductance and Self Inductance | Formula & Example

Electromagnetic induction occurs when a magnetic flux in motion with respect to a single conductor or a coil induces an emf in the conductor or coil. Because the growth or decline of current through a coil generates a changing flux, an emf is induced in the coil by its own …

Read More »## Superposition Theorem

Superposition theorem is stated as follows: The current is any circuit element or voltage across any element of a linear bilateral network is the algebraic sum of the currents or voltages separately produced by each source of energy. Simultaneous equations may be avoided in the solution of a complex network …

Read More »## Norton’s Theorem | Norton’s Equivalent Circuit

Norton’s Theorem states that: Suppose we are given an arbitrary circuit containing any or all of the following elements: resistors, voltage sources, current sources (the source can be dependent as well as independent). Let us identify a pair of nodes, say node a and b, such that the circuit can …

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