Laws of Electrical Engineering

Basic Laws of electrical engineering are stated by great inventors, who have derived the laws from their scientific innovations. They have proved the nature and behavior of electricity with their experiments.

It is utmost important to know those basic laws in order to study the electrical engineering. So enjoy reading.

Basic Laws of Electrical Engineering

Ohm’s Law

Ohm’s Law gives the relationship between Voltage, Current and Resistance in an electrical circuit, which was first discovered by the German physicist George Ohm in the year 1827.

Ohm’s Law states that,

At constant temperature, the electrical current(I) flowing through a fixed linear resistance(R) is directly proportional to the voltage(V) applied across it. 

It is given by a formula,

   

Kirchoff’s Current Law(KCL)

Kirchhoff’s current law states that the total current flowing into a node or a junction must be equal to the total current flowing out of it.

Kirchoff’s Voltage Law(KVL)

Kirchhoff’s voltage law states that the sum of all voltages around any closed loop in a circuit must equal zero.

Faraday’s Law of Electromagnetic Induction

Michael Faraday formulated the two laws of electromagnetic Induction. It is commonly referred as Faraday’s Law.

His first law states that,

when a conductor is forcefully moved or rotated in an electromagnetic field, the conductor cuts the magnetic flux, which induces an emf across the conductor.

His second law states that,

The magnitude of emf induced in a coil is equal to the rate of change of flux that linkages with the coil.

Flemings’ Right Hand rule

Fleming’s Right-hand Rule shows the direction of induced current in a generator when a conductor moves in a magnetic field. It can be used to determine the direction of current in a generator’s windings.

Fleming’s Right Hand rule states

Stretch out the fore finger, middle finger and thumb of your right hand in such a way that they are mutually perpendicular to each other. If the fore finger represents the direction of field(F), the thumb points in the direction of motion or applied force(B), then middle finger points in the direction of the induced current(I).

Flemings’ Left Hand rule

Fleming’s left-hand Rule shows the direction of motion of motor. Fleming’s Left Hand rule states

Stretch out the fore finger, middle finger and thumb of your left hand in such a way that they are mutually perpendicular to each other. If the fore finger represents the direction of the field(B) and the middle finger represents that of the current(I), then thumb gives the direction of the force(F).

Lenz’s Law

Lenz’s law states that,

The current flowing in a conductor due to the induced emf always opposes the cause producing it.

According to lenz’s law,

Cork Screw Rule

It states that,

when a corkscrew is rotated downwards in such a way that the screw moves in the direction of the current. The direction of rotation of screw gives the direction of the magnetic field.