A capacitor used for power factor correction in single phase circuit d...
Power factor improvement using the static capacitor:
Consider an inductive load taking a lagging current 'I' at a power factor cos ϕ1.
In order to improve the power factor of this circuit, the remedy is to connect such equipment in parallel with the load which takes a leading reactive component and partly cancels the lagging reactive component of the load.
The below figure shows a capacitor connected across the load.

The capacitor takes a current Ic which leads the supply voltage V by 90°. The current Ic partly cancels the lagging reactive component of the load current as shown in the phasor diagram.

The resultant circuit current becomes I′ and its angle is ϕ2.
It is clear that ϕ2 is less than ϕ1 so the new p.f. cos ϕ2 is more than the previous p.f. cos ϕ1.
The resultant circuit current I′ is less than I.
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A capacitor used for power factor correction in single phase circuit d...
Understanding Power Factor Correction
Power factor correction is an essential technique used in electrical systems to enhance efficiency. In a single-phase circuit, capacitors are commonly employed for this purpose.
Function of Capacitors in Power Factor Correction
- Capacitors provide reactive power, which can counteract the inductive effects in a circuit.
- The presence of inductive loads (like motors) causes the current to lag behind the voltage, resulting in a low power factor.
Effects of Adding a Capacitor
1. Decrease in Line Current:
- Adding a capacitor reduces the total reactive power demand of the circuit.
- As reactive power is diminished, the overall current drawn from the supply reduces since the line current is proportional to the total apparent power (S = V * I).
2. Increase in Power Factor:
- The power factor (PF) is defined as the ratio of real power (P) to apparent power (S).
- By improving the balance between real and reactive power through the addition of capacitors, the power factor increases.
- A higher power factor indicates more efficient utilization of electrical power.
Conclusion
In summary, the use of a capacitor for power factor correction in a single-phase circuit effectively decreases the line current while simultaneously increasing the power factor. Hence, the correct answer is option 'A'. This enhancement leads to improved energy efficiency and reduced electricity costs in power distribution systems.