Alternating Current Test - 5

The standard voltage and frequency of alternating current supply in India is set to 220 V and 50Hz respectively by the government of India because when power has to be transmitted from a power plant, the biggest challenge is to cut the transmission losses. For this purpose, the current value should be small and potential difference(Voltage) should be more. Also losses are minimal at 50 Hz/60 Hz frequency.

By using the phenomenon of mutual induction, transformers allow us to easily change voltage of AC. This is necessary to cut down poer losses while supplying electricity to our homes.

Alternating Current is the current in which the polarity of source continuously changes on a fixed frequency. So the positive and the negative terminals ‘alternate’.

The electrical current that flows through an AC resistance varies sinusoidally with time and is represented by the expression, I(t) = I sin(ωt + θ)
Now by ohm's law, V= IR
So, for the AC circuit, V= IR sin(ωt + θ)
Clearly both V and I have zero phase difference and hen are in phase.b

By convention phasor diagrams are made to show the rotation of phasor in counterclockwise direction with constant speed.

In the first half of the cycle, power is supplied to the inductive circuit. In the next half the inductor dissipates the energy supplied by circuit.

Thus overall no power is supplied to the circuit