Consider an ac circuit in which a resistor of R ohms and a capacitor of capacitance C Farads are connected in series as shown in figure 4.22.

AC through series R-L-C circuit

Consider an ac circuit in which a resistor of resistance R Ω, an inductor of inductance L Henry and a capacitor of capacitance C Farads connected in series across an ac supply of V volts as shown in Figure 4.25.

Let

V = rms value of applied voltage

I = rms value of resultant current