Question

How much current is drawn by the primary of a transformer while steps down 220 V to 22 V to

operate a device with an impedance of 220 Ω?​

Answer 1

Answer :

Voltage of primary coil = 220V

Voltage of secondary coil = 22V

Impedance of device = 220Ω

We have to find current flow in primary coil$.$

★ First of all we need to find power developed in secondary coil.

➝ P₂ = V₂²/R

➝ P₂ = 22²/220

➝ P₂ = 2.2 W

For an ideal transformer,

• Input power = Output power

∴ Input power will be also 2.2 W

We know that power is measured as the product of voltage and current.

Power developed in primary coil :

➝ P₁ = V₁ × I₁

➝ 2.2 = 220 × I₁

➝ I₁ = 0.01 A

∴ Current flow in primary coil will be 0.01A.