# Why Current Increases When Capacitance Increases or Capacitive Reactance Decreases?

**In Capacitive Circuit, Why the Circuit Current (I) Increases, When Capacitance (C) Increases or Inductive Reactance (X _{C}) Decreases?**

Next question from electrical and electronics engineering interviews question and answers series.

Explain the statement that ” **In a capacitive circuit, when Capacitance (C) increases or capacitive reactance (X _{C}) decreases, the Circuit Current (I) decreases**“.

**Related Question: Why Current Decreases When Inductance or Inductive Reactance Increases?**

**Explanation:**

We know that in DC circuits:

I = V / R,

But in case of AC circuits:

I = V / Z

Where “total resistance of AC circuits = Impedance = Z = √ (R^{2} + (X_{L} – XC^{2})”

In case of Capacitive circuit:

- Z = √ (R
^{2}+ X_{C}^{2}) - I = V / X
_{C}or I = V/Z

It shows that in a capacitive circuit, Current is inversely proportional to the capacitive reactance as well directly proportional to the capacitance “C” as capacitance and __capacitive reactances__ “X_{C}” are inversely proportional to each others.

Let’s check with an example to see how current reduced by capacitive reactance and increased by increasing the value of capacitor.

__When Capacitance = ____10 µF__

Suppose a capacitive circuit where:

- Capacitance = C = 10µ Farads
- Voltage = V = 220 V
- Frequency
*f*= 50 Hz

To find the capacitive reactance;

X_{C} = 1 / 2π*f*C

X_{C} = 1 / (2 x 3.1415 x 50 x 10×10^{-6})

**X _{C} = 318.3 Ω**

Finally, current in capacitive circuit:

I = V / X_{C}

I = 230V / 318.3 Ω

I = 0.72 A

Related Questions:

- Why Power Factor Decreases When Inductance or Inductive Reactance Increases?
- Why Power Factor Decreases When Capacitive Reactance Increases or Capacitance Decreases?

__When Capacitance = 60 ____µ____F__

Now we increased the value of capacitance (C) of a capacitor form 10 µF to 60 µF.

V = 220V, C = 60 µF, *f* = 50 Hz.

**X _{C}** = 1 / 2π

*f*C = 2 x 3.1415 x 50 x 60 µF =

**53 Ω**

I = V / X_{C} = 230 V / 53 Ω

I = 4.34 A

Related Questions:

- In a Capacitive Circuit, Why the Current Increases When Frequency Increases?
- In an Inductive Circuit, Why the Current Increases When Frequency Decreases?

**Conclusion:**

We can see that, When capacitance (C) was **10µF**, then circuit current were **0.72 A**,

But when circuit capacitance increased from **10 µF** to **60 µF**, then the current increased from **0.72 A** to **4.34 A**.

**Hence proved,**

**In a capacitive circuit, when capacitance increases, the capacitive reactance X _{C} decreases which leads to increase the circuit current and vise versa.**

In oral or verbal,

- Capacitive reactance is a kind of resistance. When resistance increases, the circuit current decreases and vice versa.
- Capacitance is inversely proportional to the capacitive reactance.

**C ****∝**** 1 / X _{C}**

- Current is directly proportional to the capacitance and inversely proportional to capacitive reactance.

**I ****∝**** C and I ****∝**** 1/X _{C}**

Related Questions/Answers:

- Why Flux in Primary and Secondary Winding is Always Equal?
- Why the reactance of a system under fault condition is low and faults currents may raise to the dangerously high value?
- Why Inductive Reactance (X
_{L}In DC Supply Is Zero (0)?