Question

The secondary windings of a transformer in which the voltage is stepped down are usually made thicker wire than the primary. Explain why?

Answer 1

Hint: We must know that a transformer is used to either raise or low voltages and currents in an electrical circuit. There are two types of transformers known as step-up and step-down transformers. Usually, primary windings in a transformer draw power from the source and secondary windings deliver the changed voltage to the load.

Complete step by step answer:
Firstly we will discuss transformers and different parts of a transformer. Basically a transformer consists of 3 parts. They include an iron core which provides a circuit of low reluctance for magnetic lines of force, a primary winding which receives electrical energy from source and a secondary winding which receives electrical energy by induction from the primary coil. These windings are wound on a closed core to obtain maximum inductive effect between two coils.

Now, we will discuss a step down transformer and why the secondary windings are thicker than primary windings. A step down transformer is designed as there are more turns on the primary coil than the secondary coil. Here, Induced voltage across the primary coil is greater than the applied voltage across the secondary coil. That is the voltage is stepped down.
The reason for making the secondary windings thicker is, while working on a transformer, AC current will be passing through both windings. These coils will be having a resistance and due to heating there will be energy loss. This loss can be reduced by using wires with lower resistance for winding. The voltage will be higher in the secondary coil so there is a chance for more loss. So, to reduce the temperature we use thicker wires having low resistivity.

Note:
Usually, thick copper wires are used for secondary winding. Copper has a low resistivity. We must know how thickness reduces resistance. Resistance of a conductor is directly proportional to length of the wire and inversely proportional to area of cross section/thickness. So, if we increase thickness, the resistance will reduce.