# Basic Electrical Quantities and Their Units

## Basic Electrical Quantities:

Voltage: The voltage or electric potential is the capacity of a charged body or negatively charged to do some work which is known as voltage.
Unit: The S.I unit of voltage is volt and denoted by the letter “V“. The voltage may also be defined as it drives the free electrons through a conductor from one end to the other end fully.

Electrical Potential Difference: The difference in the electrical potentials between two charged bodies is known as the electrical potential difference.
Unit: The S.I. unit of Electrical Potential Difference is Volt.

Capacitor: The capacitor is an effective device by which it can store electricity.

Capacitance: The capacitor of a condenser is the property at which it deposits a quantity of electricity between two conducting plates. It denoted by the letter “C“.
Unit: The S.I. unit of the capacitance of a condenser is farad and denoted by the letter “F“. We know that the quantity of charge,
Q=CV (Where C= Capacitance of the condenser in farad and V= Surface potential in volt, Q=coulomb)

Current: The flow of electrons in a closed circuit is known as electric current. It may also be defined as a continuous flow of charge carriers in a conductor material.
Unit: The electric current in S.I. unit is Ampere. The symbol used by the letter is ‘A‘.

Resistance: resistance is the property of a material by virtue that opposes the flow of electric current through the material.
Unit: The S.I. unit of resistance is ohm and it is denoted by the letter ‘R‘.

Inductance: When an electric current flows through a coil, a magnetic field or flux is created and the electrical energy is stored in the form of a magnetic field. The inductance is the property of a coil by virtue of which it opposes any change in current in it.
Unit: The unit of inductance is Henry (H).

Work: Work is said to be done by a force when the point of application is displaced along the direction of force or across the direction of the force against the force of gravity. It is measured by the product of force and the distance or displacement at which the force acts.
Unit: The S.I. unit of work is Newton-meter or Joule.

Power: It is rate of doing work.
Unit: The S.I. unit of power is watt.

Energy: It is the capacity of doing work. Energy=power x time.
Unit: In electrical energy the smallest unit is a watt-second or joule and the bigger unit which is used for commercial purposes is a kilowatt-hour (kW-hr).
Board of Trade unit (B.O.T) = 1 kWhr