2
\$\begingroup\$

In one my assignment questions, I need to find voltage across a capacitor. This is the diagram given:

enter image description here

And the conditions given are:

1- Switches A and B are in perfect sync, and when A opens, B closes and vice versa. Also their positions change every 30 ms.

2- Initially switch A is open. Assume steady state is achieved

And the question is to find voltage across capacitor at time instances:

  1. t=0+ and 0-
  2. t=50ms+ and 50ms-
  3. 60 ms

So considering the open switch and steady state condition of capacitor (acts as open circuit). I reduced the circuit to this:

enter image description here

The voltage across capacitor will be same as voltage across the 7 ohm resistor.

Applying current division and also taking into consideration the 3A current through the 7 ohm resistor, I got voltage across the resistor as approx 23.205 Volts.

Also as this is a forced response, the voltage across capacitor will be Vc = Vo - Voe^(-t/RC)

So at t=0+ and 0-, i.e steady state Vc = Vo = 23.205 volts.

But I am unable solve for the other parts i.e 50ms and 60ms as I am not sure how to take into account the position change in both the switches. How do I go about it ?

\$\endgroup\$
2
  • \$\begingroup\$ think about this ... when does the current from the 10 A source flow on the left side of switch A? \$\endgroup\$
    – jsotola
    Mar 12, 2021 at 7:28
  • \$\begingroup\$ +1 for identifying this as an assignment and showing some work. \$\endgroup\$ Mar 12, 2021 at 15:03

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.