In general, the primary and secondary windings in a transformer possess the same amount of inductance. This means that there is equal voltage and current levels in both circuits. There are circumstances, however, when voltages don’t match. For example, imagine that your electricity runs at 220 volts, but you have a 120V device, which is the standard for a great deal of U.S. equipment. In order for the equipment to function properly, the input voltage has to match the 120 volts and higher current running through the equipment.
This is where a step down transformer becomes useful. A step down transformer is one whose secondary voltage is lower than its primary voltage. The transformer converts high-voltage, low-current power to low-voltage, high-current power. In other words, it transforms electrical voltage from a given level to a lesser level, which is how the term step down originated. Here’s how it works: a step down transformer is made from at least two wires wound around an iron core. When voltage is applied to the primary (or input) coil, the core becomes magnetic, and this magnetic induction produces a voltage in the secondary (or output) coil. For all step down transformers, the ratio of the turns on the two sets of windings determines the amount of voltage transformation. This means that if there were 50 turns on the primary coil, there would need to be 25 turns on the secondary coil in order to halve the voltage.
The formula for step down transformers is as follows:
Voutput = Vinput * Nsecondary
where V stands for voltage and N stands for the number of windings on any given coil.
Conversely, if you needed to increase voltage, a step up transformer would be used instead. This means that there would be a smaller input voltage and the output would be proportionately greater, depending on the number of turns in the secondary coil as compared to the lesser-wound primary coil. Both step up and step down transformers convert current, but neither is capable of producing or creating it.
To learn more about step down transformers and how they might benefit you, our professionals at CET Technology are happy to help.