How does an electrical transformer work?

An electrical transformer is a static alternating current machine that allows some function of the current such as voltage or current to be varied while maintaining the frequency and power, in the case of an ideal transformer. To do this, it transforms the electricity that reaches the input winding into magnetism in order to transform it back into electricity, under the desired conditions, in the secondary winding.

These elements are widely used in the electricity grid, since once the electricity has been generated in the generator of the power stations, and before sending it to the grid, step-up transformers are used to raise the voltage and thus reduce the losses in transport caused by the Joule effect. Once it has been transported, step-down transformers are used to give this electricity values with which we can work.

They are also used by most household appliances and electronic devices, as they normally work at lower voltages than those supplied by the mains.

They also form part of a key element in household electrical safety: the residual current device. This device uses transformers to compare the current entering and leaving the home. If the difference between these is greater than 10 mA, it disconnects the circuit, preventing us from suffering injuries.