Transformers, types and uses.

Transformers are widely used electrical devices today, but do you know what a transformer is, what is it for and where are they used? Here you will clarify all these doubts and more. Come on, guys!

Transformers are devices that operate in alternating current, their purpose is to convert the voltage applied to the primary coil or primary winding, the input, raising or reducing the voltage in the secondary coil or secondary winding, the output of the transformer.

They are widely used for voltage conversion for domestic or industrial equipment, where the equipment voltages are not compatible with the voltage provided by the local utility. Now know some types of transformers.

Safety transformers:

Safety transformers, as the name implies, are responsible for the safety of the equipment they are supplying, not allowing a current or voltage to arrive in the device that could damage it. This protection is made through special insulation that does not allow contact between the primary winding and the secondary winding, or even contact between one of the coils with the core. Bell transformers, toy transformers and isolator transformers are considered safety transformers.

What is the voltage transformer?

Toy Transformers:

They are the transformers used in toys where their secondary voltage does not exceed 24 volts. In these models of transformers, there is the possibility of a short circuit, if this occurs, its short voltage is relatively high, limited only by the action of internal resistances and dispersion fields.

Bell transformers:

The bells need little voltage to work, a voltage that is limited to a maximum of 12 volts, so your transformer has enough windings on the secondary turns for the desired voltage. It must be understood that the bells are very easy to close short because their internal resistances are very low, we can even say that each actuation is equivalent to a short in the secondary winding of the transformer.

Isolation Transformers:

This transformer model is a traditional model, used in homes to supply equipment that works with voltages opposite to those available by concessionaires, being possible to power a single device, even though its working current must not exceed 16 amps. In single-phase systems, 250V isolation transformers are used and when it is three-phase systems, 380V transformers are used.

Adjustable transformers

Standard transformers occasionally use the method of doubling or halving the input voltage. The adjustable transformers, on the other hand, allow a greater possibility for choosing the voltage that will come out of the transformer to supply certain equipment, this model of transformer is widely used when the use of several devices with different application voltage is necessary.

There are two methods to make this voltage variation possible, varying the number of turns of the secondary winding and varying the intensity of the magnetic dispersion field.

Adjustable transformers with variation in the number of turns:

Its method of operation works with the variation of the number of turns in its secondary winding, where there are several derivations in which the loads are connected.

Adjustable transformers with varying dispersion fields:

The dispersion fields decrease the induction in the secondary winding, the larger this dispersion field, the more intense and stronger this effect will be if we vary the dispersion we have a second alternative which is to vary the voltage at the output.

There are several ways to interfere in the dispersion field, one of them is used a transformer with dispersion game, because when the game fits fully in the core it reaches maximum dispersion and, when the game is as far outside the core as possible, it reaches the minimum.

Instrument transformers:

They are used in electrical measurement instruments, such as multimeters, and their use is mainly recommended for measurements at high voltages and currents, as the transformer can isolate the devices, thus reducing their high voltages and currents, to facilitate the measurement.


Autotransformers are different from all transformers listed above, they are composed of only one winding, where it can be considered as primary or secondary.

An autotransformer is an electrical machine that can do the same power induction to a circuit, with a change in voltage and current, but unlike the transformer, only one winding is used for this, according to the desired transformation in a given part of the winding. a “tap” and at this point, we will have values ​​different from those found at the input of the autotransformer.

The main difference between autotransformers and transformers is that it transmits only a part of the electric current by induction, the rest is done by conducting the electric current.