What is the initial voltage of the capacitor in this circuit?

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Homework Help Overview

The discussion revolves around determining the initial voltage across a capacitor in a circuit connected to a DC source. The subject area involves concepts related to capacitors and circuit analysis.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of the circuit being open before a certain time, questioning how charge could flow into the capacitor. There is also a discussion about the potential difference across the capacitor given its connection to a voltage source.

Discussion Status

The discussion is active, with participants raising questions about the assumptions regarding the circuit's configuration and the behavior of the capacitor. Some clarification has been reached, but there is no explicit consensus on the initial voltage value.

Contextual Notes

There are references to conflicting information regarding the initial voltage of the capacitor, with some participants noting a potential misunderstanding of the circuit's behavior before a specific time.

Abdulwahab Hajar
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Homework Statement


I would like to know the initial voltage across the capacitor terminals in the following diagram.

Homework Equations


when a capacitor is connected to a DC source for a long time, it acts an open circuit.

The Attempt at a Solution


for t < 0, we get the diagram below and I believe the voltage should be 12V right?
just making sure, because In an online solution it said the voltage is 0, if so why?
Thank you
 

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Before t = 0 the circuit is open at b. How could charge flow into the capacitor?
 
gneill said:
Before t = 0 the circuit is open at b. How could charge flow into the capacitor?

but isn't one of the terminals of the capacitor connected to the 12V source?
while the other is just simply disconnected... shouldn't that incur a potential difference between the two plates
 
gneill said:
Before t = 0 the circuit is open at b. How could charge flow into the capacitor?

never mind sir, I get it... very silly mistake
thanks though
 

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