# The voltage of primary and secondary coil of transformer is same?And current is same or not?

##### 1 Answer

Feb 7, 2018

Generally both voltage and current will change from primary to secondary coils.

#### Explanation:

What will remain constant (assuming 100% efficiency) is the power on both sides, and power is the *product* of current and voltage (I.e.

The most useful equation (again assuming it is efficient) is the ideal transformer equation: