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Updated: Aug 9, 2023

The transformer is a static piece of equipment by means of which electrical power is transformed from one alternating-current circuit to another with the desired change in voltage and current, without any change in the frequency.

Basic Transformer

The basic transformer is shown below

Basic Transformer
Basic Transformer

Working of Transformer

The working principle of the transformer is mutual #induction. It states that when two coils are inductively coupled and if the current is changed uniformly in one coil then #emf gets induced in the other coil.

The basic transformer shown above consists of two inductive coils which are electrically separated but linked through a common magnetic circuit. The mutual inductance of the two coils is high.

The supply is given to the primary winding and load is connected to the secondary winding. The number of turns in the primary winding is generally denoted by N1 and the number of turns in the secondary winding is generally denoted by N2.

Based on the number of primary and secondary turns of a transformer, they can be either step up or step down transformers.

Step-up transformer:

Step-up transformer
Step-up transformer

The Step-up transformers have more number of turns on the secondary side and the emf induced in a step-up transformer is more than the input signal.

Step down transformer:

Step-down transformer
Step-down transformer

Step-down transformers have more number of turns on the primary side and the emf induced in the step-down transformer is less than the input signal.

When the input supply voltage is given to the primary winding of a transformer the electrical power is transformed into the magnetic field. An alternating #flux is produced which completes its path through the common magnetic core. The alternating flux therefore links with the secondary winding and mutually induced e.m.f is developed in the secondary winding. This induced e.m.f. drives the load. Thus electrical energy is #transferred from primary to secondary even though there is no #electrical contact.

How does energy transfer from powerhouses to our homes?

Have you ever wondered how does energy transfers from powerhouses to our homes? Let us understand it.

The figure below illustrates how electricity is transferred from power stations to our homes

The electricity reaches our houses by passing through different networks like power grid station, transmitting substation, transmission Network, Receiver substation, Distribution network, Consumer.

Power Grid Station:

Electricity is produced in power stations (#powerplants). Generally, Electricity is generated at a power plant by Electromechanical generators . Electromechanical generators are primarily driven by nuclear fusion. There are other methods by which electricity is generated such as kinetic energy of flowing water and winding. Other sources are photovoltaics and geothermal power.


The wires used in the power lines have imperfections in the metal, they are not perfect conductors and try to oppose current flowing through the wires. The longer power lines offer more resistance and thus results in electrical power loss. Substations are located near the power grid. Substations use step-up transformers to increase the voltage produced at the power stations to higher voltages and helps the power to travel long distances effectively.

Transmission Network:

The electricity from substations is transferred to the transmission Network that passes the electricity to the distribution network from the power substations. It helps in the delivery of electricity to end-users. The voltages are still high as the electricity has to reach long distances.

Receiver Substation:

The voltage increased with the step-up transformer is to be decreased again as the home appliances cannot bear the high voltages. To decrease the voltage to the required level step-down transformers are used at the Receiver Substation. The voltage is brought down to safe and standard levels and the electricity reaches the distribution network from the transmission networking.

Distribution Network:

The electricity from the substation transformer enters the distribution network lines to reach the destination. After reaching a neighborhood, the electricity is passed through small street transformers to further decrease the voltage level to ensure safety while using it.


Finally, the electricity is passed through service drop and the meters at our home records power consumption according to the usage. It divides into the circuits of our house and transmits through the wires to power the switches.


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Written By: Nagapuri Swathi

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