What is a Pure Resistive AC Circuit?

The value of current will be maximum when ωt= 90° or sinωt = 1.Putting the value of sinωt in equation (2) we will get

Power in Pure Resistive Circuit

The power curve waveform uses three colors—red, blue, and pink—to represent the current, voltage, and power curves, respectively. The phasor diagram confirms that current and voltage are in phase, meaning their peaks occur simultaneously. As a result, the power curve remains positive for all voltage and current values.

In a DC circuit, power is defined as the product of voltage and current. Similarly, in an AC circuit, power is calculated using the same principle, though it considers the instantaneous values of voltage and current. Thus, the instantaneous power in a pure resistive circuit is expressed by:

Instantaneous power: p = vi

 The average power consumed in the circuit over a complete cycle is given by

As the valve of cosωt is zero.So, putting the value of cosωt in equation (4) the value of power will be given by

Where,

• P – average power
• V_r.m.s – root mean square value of supply voltage
• I_r.m.s – root mean square value of the current

Hence, the power in a purely resistive circuit is given by:

In a pure resistive circuit, voltage and current are in perfect phase with a zero phase angle, meaning no phase difference exists between them. The alternating quantities reach their peak values at the same time intervals, and the rise and fall of voltage and current occur simultaneously.