For the circuit diagram shown below, calculate the voltage across capacitor V(t) at t = 160 μs?
For the circuit diagram shown below, calculate the voltage across capacitor V(t) at t = 160 μs? Correct Answer 18.4 V
Concept:
The voltage across the capacitor Vc(t) is given by the following transient equation.
Vc(t) = Vc(∞) + (Vc(0+) – Vc(∞)) e-t/τ
Calculation:
At t = 0-, the capacitor acts as an open circuit. The voltage across the capacitor is,
Vc(0-) = 50 V
At t = 0+, as the capacitor does not allow the sudden change in voltage,
Vc(0-) = Vc(0+) = 50 V
At t = ∞, as there is no source, the voltage across the capacitor is zero.
Vc(∞) = 0 V
Time constant τ = RC = 80 × 2 μ = 160 μ
Now, Vc(t) = Vc(∞) + (Vc(0+) – Vc(∞))e-t/τ
Vc (160 × 10-6) = 50 e-160 μ/160 μ
= 50 e-1
Voltage across capacitor Vc(t) = 18.39 V
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Feb 20, 2025