A 60 W load is connected to the secondary of a transformer whose primary draws line voltage. If a current of 0.54 A flows in the load, what is the current in the primary coil? Comment on the type of transformer being used.

Question

Philoid · Accepted Answer

Given:
Power in the secondary coil: P_S = 60 W
Current through the secondary coil: I_S = 0.54 A
Voltage in the primary coil: Line voltage = V_P = 220 V
Formula used:
Power is given as
P= VI
Where V is the voltage and I is the current flowing.
Thus

Here, V_S is the Voltage in the secondary coil, P_S is the power of the secondary coil and I_S is the current through the secondary coil

∴ V_S = 111.11 V
Since V_S < V_P, transformer is a step down transformer.
We know that proportions

Hence current through the primary coil is 0.272 A.