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

In this section, we will calculate an equivalent inductance of inductors in series and inductors in parallel. Inductors in Series The method for determining the total inductance of the following circuit is similar to that used for series resistors. According to Kirchhoff’s voltage law, we can write following equation for the …

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 …

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

Thevenin’s Theorem Definition 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 be …

Read More »## Star Delta Transformation and Delta Star Transformation

Wye (Star) and Delta networks identified for conversion in converting between types. In the Wye (Star) networks, each resistor is named for the terminal it is connected to: Ra, Rb, and Rc. For the Delta (Pie) networks, each resistor is named for the two terminals it is connected across: Rab, …

Read More »## Metric Units of Measurement SI Units

SI units are most widely used units of measurement belong to an international system of units which is also known as SI or Metric System. SI comprises of three main categories which are prefixes, base units and derived units. SI base units are seven which are defined as; Length (Meter) …

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