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Given the following circuit:

schematic

simulate this circuit – Schematic created using CircuitLab

I'm trying to find the equivalent capacitor assuming that the capacitors are already charged. I'm aware that C1 and C2 are in parallel, therefore they must have the same voltage. What I'm not too sure about is if I can just add both of their capacitance since the resistance R is only connected to C2, but at the same time C2 instantly affects C1 keeping the voltages equal.

Just to clarify, by equivalent capacitor I'm referring to this:

schematic

simulate this circuit

Thanks

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If C1 and C2 are parallel, and R is parallel with C2, then R is parallel with both C1 and C2.

This is a dc problem, so we assume that there is no transient behavior. The resistor has discharged the capacitors, so the voltage across every element is zero.

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  • \$\begingroup\$ That was my initial guess but since R wasn't "directly" parallel with C1 and C2 it kind of threw me off. Just had to double check, thanks for answering. \$\endgroup\$ – rr1303 May 7 '19 at 15:44
  • \$\begingroup\$ But R is directly parallel with both C1 and C2! There is only parallel, and if both ends of the two elements are connected together then they are electrically paralllel. Don't get confused by how the schematic is drawn, what matters are the connections. \$\endgroup\$ – Elliot Alderson May 7 '19 at 20:13
  • \$\begingroup\$ That was precisely what I was referring to in my last comment hence the speech marks in directly. Everything has already been understood. \$\endgroup\$ – rr1303 May 7 '19 at 21:21

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