Question

How do capacitors work in AC circuits?

Answer 1

Hint: Capacitor is a passive device which stores energy and does not dissipate energy. AC circuits are the one which have alternating currents flowing in the circuits.

Complete step by step answer:
Capacitors are the passive devices which store electrical energy in the form of electric fields. The effect of a capacitor is known as capacitance. Capacitors are of different types such as mica capacitor, paper capacitor, electrolytic capacitor, ceramic capacitor and plastic capacitors.

Capacitor formula is given by:
$C = \dfrac{{{\varepsilon _0}A}}{d}$ (A of the plates, d is the distance between the plates of the capacitor and ${\varepsilon _0}$ is permittivity of free space)
The property of a capacitor to block current flowing through it is called its reactance. Reactance of the capacitor is given by;
${X_c} = \dfrac{1}{{2\pi fC}}$

Therefore, when the Dc current is made to flow through the capacitor, it gets blocked by the capacitor because DC current has zero frequency and when the frequency of the current is zero, reactance of the capacitor will become infinite. Capacitor will act as an open circuit for dc.

Similarly, when AC current is made to flow through the capacitor its reactance value will become zero and current will get the clear path to flow through. AC current has higher frequency which makes the reactance of the capacitor tends to zero and capacitor will act as a short circuit for AC.

Note: Capacitors have many applications, we will discuss a few; capacitors are used for improving the power factor of the transmission lines, because capacitors have leading power factors. Capacitors are used in voltage divider circuits, clipper, clamper, voltage doublers circuit. Capacitors are also used in inverter circuits as well.