Working Principle of Transformer (Transformer)

Working Principle of Transformer (Transformer)

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Working Principle of Transformer (Transformer)

A transformer (transformer) is a device used to increase or decrease the alternating voltage (AC).

The transformer consists of 3 main components, namely:

The first (primary) co...

Working Principle of Transformer (Transformer)

A transformer (transformer) is a device used to increase or decrease the alternating voltage (AC).

The transformer consists of 3 main components, namely:

The first (primary) coil which is the input.
The second coil (secondary) is the output.
Iron core which serves to strengthen the magnetic field generated.

transformer 1

transformer 2

The working principle of a transformer or transformer is that when the primary coil is connected to an alternating voltage (AC) source, changes in the electric current in the primary coil cause a changing magnetic field. The changing magnetic field is strengthened by the presence of an iron core and is conveyed by the iron core to the secondary coil, so that at the ends of the secondary coil an induced emf will arise.
This effect is called mutual inductance.

transformer 3

In the transformer schematic in Figure 3, when the electric current from the voltage source flowing in the primary coil reverses direction (changes its polarity) the resulting magnetic field will change direction so that the electric current generated in the secondary coil will change its polarity.

The relationship between the primary voltage, the number of primary turns, the secondary voltage, and the number of secondary turns, can be stated in the equation:

rumus trafo1

Vp = primary voltage (volts)
Vs = secondary voltage (volts)
Np = number of primary turns
Ns = number of secondary turns

Transformer Symbol

Based on the comparison between the number of primary turns and the secondary turns of the transformer, there are two types, namely:

A step-up transformer is a transformer that converts a low alternating voltage to a high one, this transformer has a number of secondary turns more than the number of primary turns (Ns> Np).

2. A step down transformer is a transformer that converts a high alternating voltage to a low one, this transformer has a higher number of primary turns than the number of secondary turns (Np> Ns).

In the transformer (transformer) the amount of voltage issued by the secondary coil is:

1. In proportion to the number of secondary winding (Vs ~ Ns).
2. In proportion to the magnitude of the primary voltage (VS ~ VP).
3.Inversely proportional to the number of primary turns,

rumus trafo2

So that it can be formulated:

rumus trafo3

Use of a transformer

Transformers (transformers) are used in electrical equipment, especially those that require a change or adjustment of the amount of alternating voltage. For example, the radio requires a voltage of 12 volts even though electricity is from the PLN 220 volts, so a transformer is needed to convert an alternating electric voltage of 220 volts to an alternating voltage of 12 volts.

Examples of electrical devices that require a transformer are:

- TV
- Computer
- Fotocopy machine
- Power house
- Etc.

An example of how to calculate the number of secondary turns:

To turn on a 10 volt lamp with a power supply voltage of 220 volts PLN is used a step down transformer. If the number of primary turns of the transformer is 1,100, what is the number of turns on the secondary coil?


You know: Vp = 220 V
Vs = 10 V
Np = 1100 turns

Asked: Ns = ...........?


rumus trafo4


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