1. TRANSFORMERS

2. TRANSFORMER PARAMETERS Turns Ratio (n) It is defined as the ratio of the number of turns in the secondary winding (N sec ) to the number of turns in the primary winding (N pri ) n= N sec / N pri

3. Direction of windings

4. Relationship between primary and secondary voltages and the turns ratio The ratio of secondary voltage (V sec ) to primary voltage (V pri ) is equal to the ratio of the number of turns in the secondary winding (N sec ) to the number of turns in the primary winding (N pri ) V sec / V pri = N sec / N pri = n V sec = n V pri For a step up transformer n > 1 For a step down transformer n < 1

5. Impedence Matching It is the technique of Matching of a load resistance to a source resistance in order to achieve maximum power transfer.

6. Maximum Power Transfer Theorem When a source is connected to a load, maximum power is delivered to the load when the load resistance is equal to the fixed internal source resistance

7. TRANSFORMER POWER RATING Volt Amperes (VA) Primary / secondary voltage Operating frequency Eg:- 2 kVA, 500/ 50, 60 Hz

8. TRANSFORMER AS AN ISOLATION DEVICE DC Isolation

9. Power line isolation