Electrical Rudiments

Electrical Rudiments

What is Voltage....?

The difference in electric potential energy per unit charge between two points. Voltage is the work to be done, upon an unit charge to move between two points, against a electric field. A Voltage which is a measure of electric potential difference, is the cause of Electrical Current to flow in a closed circuit.

What is Current....?

the rate of flow of electric charge through a conducting medium with respect to time. It is caused by drift of free electrons through a conductor to a particular direction.

Unit of current is Coulombs per second and this logical unit of current has a specific name Ampere

For better understanding, let me give an example, suppose total 100 coulombs of charge is transferred through a conductor in 50 seconds.

As the current is nothing but the rate at which charge is transferred per unit of time, it would be ratio of total charge transferred to the required time for that. Hence, here

What is Resistance...?

Electrical resistance may be defined as the basic property of any substance due to which it opposes the flow of current through it.

Ohm's Law:

The statement is simple and it says that whenever a potential difference or Voltage is applied across a Resistor of a closed circuit, Current starts flowing through it.

What is Power...?

Electric power is the rate of energy consumption in an electrical circuit.

The electric power is measured in units of watts.

P is the electric power in watt (W).

E is the energy consumption in joule (J).

t is the time in seconds (s).

P = V · I

P = I ² · R

P = V ² / R

What is kW...?

Kilowatt (symbol: kW) is a unit of electric power.

One kilowatt (kW) is equal to 1000 watts (W):

1kW=1000W

Kilowatt-hour: 

Kilowatt-hour is an energy unit (symbol kWh or kW·h).

One kilowatt-hour is defined as the energy consumed by power consumption of 1kW during 1 hour:

1kWh=1kW*1h

What is kVA...?

kVA is kilo-volt-ampere. kVA is a unit of apparent power, which is electrical power unit.

1 kilo-volt-ampere is equal to 1000 volt-ampere:

1kVA = 1000VA

1 kilo-volt-ampere is equal to 1000 times 1 volt times 1 ampere:

1kVA = 1000·1V·1A

Similarly 

MVA = Mega volt amp

1MVA = 1000kVA

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Next Section contains about Transformers.