Question

A source of a.c voltage V = V₀ sin ωt is connected to a series combination of a resistor 'R' and a capacitor 'C'. Draw the phasor diagram and use it to obtain the expression for (i) impedance of the circuit and (ii) phase angle.

Answer 1

The Pythagoras theorem gives

Substituting the value of v_RM and v_cm into this equation, gives

The circuit diagram and the phasor diagram, for the given circuit, are as shown.

Derivation,

The voltage equation, for the circuit, can be written as:

The phasor relation, whose vertical component gives the above equation, is