The tap switch is located on top of the tap and is associated with changing the turn ratio of a transformer. This change contributes to the change in overall voltage and affects the current distribution in different parts of the device.
The turn ratio is very important in this regard. It allows the tap to reach the desired voltage. For better functioning, the turns should be kept at 7 or 12. A slight increase or decrease in the number of turns can dramatically impact the overall abilities of the transformer.