At time t=0, a battery of 10V is connected across points A and B in the given circuit. If the capacitors have no charge initially, at what time (in seconds) does the voltage across them become 4 volt?
Solution:
Equation of charging of capacitor V = V₀(1 - e⁻ᵗ/ReqCeq) Req = 2 × 2/(2 + 2) = 1 MΩ Ceq = 2 + 2 = 4 μF V = V₀(1 - e⁻ᵗ/⁴) where V₀ = 10V and V = 4V ⇒ 4 = 10(1 - e⁻ᵗ/⁴) ⇒ e⁻ᵗ/⁴ = 3/5 ⇒ t/4 = ln5 - ln3 ⇒ t = 4(ln5 - ln3) ≈ 2 sec