Difference Between Step Up and Step Down Transformer

Step Up Transformer

1. The transformer used to change a low voltage alternating e.m.f. to a high voltage alternating e.m.f. (of same frequency) is called a step-up transfomer.
2. It increases the a.c. voltage and decreases the current.
3. The turns ratio Ns/Np > 1 i.e., it has more number of turns in the secondary coil than in the primary coil.
4. The wire of primary coil is thicker than that in the secondary coil.

Step Down Transformer

1. The transformer used to change a high voltage alternating e.m.f. to a low voltage alternating e.m.f. (of same frequency) is called a step-down transformer.
2.  It decreases the a.c. voltage and increases the current.
3.  Its turns ratio Ng/Np <1 i.e., it has less number of turns in the secondary coil than in the primary coil.
4. The wire in the secondary coil is thicker than that in the primary coil.