Circuit Theory

RC CIRCUIT - BASICS

What happens???

What happens when we connect a resistor in series with a capacitor???

1 A1 F1 V

Let us assume an $1\;A$ rating wire is connected to a capacitor $(1\;F)$ and a battery $1\;V$. $$C=\frac{Q}{V}$$$$Q=CV=1$$

The above capacitor can charge upto $1$ coulomb. Since we are using $1\;A$ rating wire, $$I=\frac{Q}{t}$$$$t=I×Q=1\;s$$we can say, it will take $1\;sec$ for the total charge to flow through this wire.

Now assume a resistor of $1\;k\Omega$ is connected in between the battery and the capacitor.$$I=\frac{V}{R}$$$$I=\frac{1}{1×10^{3}}$$$$I=1×10^{-3}$$$$I=1\;mA$$So, this resistor will limit the flow of current through the capacitor. Hence$$t=\frac{Q}{I}$$$$t=\frac{1}{1\;mA}$$$$t=1000\;secs$$it will take approximately $1000\;secs$ for the total charge to flow through the resistor.

From the above discussion, we can say connecting a resistor in series with the capacitor will slow down the charging-discharging process. This slow down is technically termed as RC delay.

When we connect a resistor in series with a capacitor, it will slow down the charging-discharging process.