The correct answer is: B. secondary side.
Tappings are provided on the secondary side of a transformer to obtain different output voltages. The number of tappings and their positions depend on the type of transformer and its application.
Tappings are used in transformers to obtain different output voltages. The output voltage of a transformer is determined by the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. By changing the number of turns in the secondary winding, the output voltage can be changed.
Tappings are usually provided on the secondary side of a transformer because the secondary winding is the one that delivers the output voltage. The number of tappings and their positions depend on the type of transformer and its application.
For example, a transformer that is used to power a 120-volt appliance may have two tappings on the secondary winding, one for 120 volts and one for 240 volts. The appliance can be plugged into either tapping to obtain the desired voltage.
Tappings are also used in transformers to provide a variable output voltage. This is done by providing a number of tappings on the secondary winding that are connected to a switch. The switch can be used to select the desired output voltage.
For example, a transformer that is used to power a variable speed motor may have six tappings on the secondary winding, each of which provides a different output voltage. The motor speed can be changed by selecting the desired output voltage.
Tappings are an important feature of transformers that allow them to be used in a variety of applications.