Electrical Engineering - Transformers - Discussion

When an additional wire is connected across the exact middle point of the secondary winding of a transformer, it is called a center tapped transformer. The wire is adjusted such that it falls in the exact middle point of the secondary winding and is thus at zero volts, forming the neutral point for the winding. This is called the "center tap" and this thing allows the transformer to provide two separate output voltages which are equal in magnitude, but opposite in polarity to each other. In this way, we can also use a number of turn ratios from such a transformer.

Center tap connection always taken secondary winding of a transformer on midpoint.

(CT) is taken at the midpoint of an auto transformer.