Interactive Solution 22.61 offers one approach to problems such as this one. The secondary coil of a step-up transformer provides the voltage that operates an electrostatic air filter. The turns ratio of the transformer is 44:1. The primary coil is plugged into a standard 120-V outlet. The current in the secondary coil is 1.9 x 10-3 A. Find the power consumed by the air filter.

Since the secondary coil of a step-up transformer provides the voltage that operates an electrostatic air filler, therefore the power consumed by the air filter will be the power in the secondary coil of the transformer.

We will use the transformer formula below to calculate the current and voltage in the secondary coil.

Ns/Np = Vs/Vp = Ip/Is where;

Ns/Np is the turn ratio of the transformer = 44/1

Vs is the voltage in the secondary coil

Vp is the voltage in the primary coil = 120V

Is is the current in the secondary coil = 1.9×10^-3A

Ip is the current in the primary coil

Power consumed by the secondary coil= IsVs

To get Vs using the relationship

Ns/Np = Vs/Vp

44/1 = Vs/120

Cross multiplying;

Vs = 120×44

Vs = 5280volts

Since Is = 1.9×10^-3A

Power consumed by the secondary coil= 1.9×10^-3A × 5280

= 10.03Watts

Since the power consumed by the secondary coil is 10.03watts, therefore the power consumed by the air filter is 10.03watts.