No, we’re not talking about turning cars into robots. A step-down transformer is one whose secondary voltage is smaller than the primary voltage, but whose secondary current is greater than the primary current, as seen in the diagram below. The greater current makes up for the smaller voltage, giving the same wattage as the original. The step-up transformer, on the other hand, is the exact opposite of the step-down transformer. Its secondary voltage is greater than its primary voltage.
How are the voltage levels transformed? When electricity is introduced into the transformer, it runs through the coils of wire wound around the iron core. In the diagram, the wire is composed of 50 turns. The core is then magnetized, which results in the electricity being transferred to the other coil of wire. And since in the diagram, the wire only has 10 turns, the voltage will turn out to be smaller. In the step-up transformer, the counterpart of the step-down transformer, the opposite happens, wherein the primary coil has less turns than the secondary coil.
Now, why do we need transformers? These are built to make the voltage supply compatible with the voltage requirement of the appliance. Step-down transformers “step down” the voltage supply to match the smaller voltage requirement of the appliance.
To your left is an example of a typical transformer used at home or in the office. As you can see, it has both step-up and step-down functions in one device. Typically, the voltages used in most homes and offices are 110V and 220V; as a result, the typical step-up or step-down transformer switches between 110V and 220V.
Even though most appliances operate under these voltages, you still have to be careful when plugging in your appliances. Always check the labels for the proper voltages, and of course, the labels of the transformers before you purchase them. You don’t want to end up buying, or worse, using the wrong transformer. If you have any trouble determining these things, it is always a good idea to consult a technician, or even the clerk of your hardware store. They are well trained and well educated with these things so as to help as much customers as they can. It is, after all, better to be aware of these things than be ill informed and then end up in trouble. Bottom line is: be careful.
As a final note, another good thing about transformers, besides the fact that they appropriate the voltage supply to the voltage requirement so as not to blow anything up, is that they have long life expectancies, if taken care or maintained properly. So make sure to invest in a transformer that you know will serve you well!