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

AI Thread Summary
The discussion centers on determining the initial voltage across a capacitor in a circuit connected to a 12V DC source. It is clarified that when a capacitor is connected to a DC source for a long time, it behaves as an open circuit, meaning no current flows into it. Before t = 0, the circuit is open, preventing any charge from accumulating on the capacitor, leading to a voltage of 0V across its terminals. Despite one terminal being connected to the 12V source, the disconnection at the other terminal means there is no potential difference. The participant acknowledges their misunderstanding and resolves the confusion regarding the voltage.
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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