Question

The time constant of the given circuit is:

• A. RC
• B. 2RC
• C. 3RC
• D. 4RC

Answer 1

The correct option is B 2RC

The equivalent resistance of the circuit, $R_{eq}=\frac{R\times R}{R+R}+R=\frac{R}{2}+R=\frac{3R}{2}$

As we know, time constant of CR- circuit, $\tau =C_{eff}{R}_{eff}$

So for the given circuit, $\tau =\frac{4C}{3}\times \frac{3R}{2}=2RC$

$\tau =2RC$