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How to find the voltage across the capacitor, under DC conditions?

I do know that under DC conditions, the capacitors will be open-circuited.

Since it is open-circuited,


simulate this circuit – Schematic created using CircuitLab

Current will be 1A

V1=30V V2=40V

Why won't the voltage across the capacitor be affected by the 50ohms and 10ohms resistor? Instead of it being parallel to the voltage across 30ohms and the 60V and 20ohms branch?

  • 2
    \$\begingroup\$ Open-circuited means that no current will flow through 50ohms resistor thus no voltage drop across 50ohms resistor. So, C1 voltage is equal to a voltage drop across 30ohms resistor and C2 voltage is equal to a voltage dropa across 30+10 ohms resistors. \$\endgroup\$
    – G36
    Commented Aug 31, 2020 at 3:26
  • 1
    \$\begingroup\$ \$V_{C1} = 60V * \frac{30\Omega}{20\Omega + 10\Omega + 30\Omega} = 30V \$ and \$V_{C2} = 60V *\frac{30\Omega + 10\Omega}{20\Omega + 10\Omega + 30\Omega} =40V\$ \$\endgroup\$
    – G36
    Commented Aug 31, 2020 at 3:29

1 Answer 1


Why won't the voltage across the Capacitance be affected by the 50ohms [resistor]

Since the question asks you to consider DC conditions, the current through the 50 ohm resistor is 0 (because it is in series with a capacitor). Therefore the voltage across it is also 0.

... and 10ohms resistor?

The voltage across the 10 ohm resistor affects the current through the 20 ohm resistor, and therefore it does affect the voltage across "the capacitor" (which I put in quotes because there are two capacitors in your circuit, so you should be more careful in naming them).


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