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

In summary, the initial voltage across the capacitor terminals in the given diagram is 12V. This is because before t = 0, the circuit is open at b and there is no way for charge to flow into the capacitor. As one terminal of the capacitor is connected to the 12V source and the other is disconnected, there is a potential difference between the two plates. This means that the initial voltage across the capacitor is 12V.
  • #1
Abdulwahab Hajar
56
2

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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  • #2
Before t = 0 the circuit is open at b. How could charge flow into the capacitor?
 
  • #3
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
 
  • #4
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
 

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

1. What is the initial voltage of a capacitor?

The initial voltage of a capacitor refers to the voltage that is present across the capacitor when it is first connected to a circuit. This voltage is determined by the charge stored in the capacitor and the capacitance value of the capacitor. It is important to note that the initial voltage of a capacitor may change as the capacitor discharges or charges in a circuit.

2. How is the initial voltage of a capacitor calculated?

The initial voltage of a capacitor can be calculated using the formula V = Q/C, where V is the initial voltage in volts, Q is the charge in coulombs, and C is the capacitance in farads. This formula is based on the relationship between voltage, charge, and capacitance in a capacitor.

3. Why is the initial voltage of a capacitor important?

The initial voltage of a capacitor is important because it affects the behavior of the capacitor in a circuit. It determines the amount of charge that can be stored in the capacitor and how quickly the capacitor can discharge or charge in a circuit. The initial voltage also plays a role in the overall energy storage capacity of the capacitor.

4. Can the initial voltage of a capacitor be changed?

Yes, the initial voltage of a capacitor can be changed by altering the charge or capacitance of the capacitor. For example, by increasing the charge or capacitance, the initial voltage will also increase. This can be done by connecting the capacitor to a power source or by changing the physical properties of the capacitor.

5. How does the initial voltage of a capacitor affect the overall circuit?

The initial voltage of a capacitor can affect the overall circuit in various ways. It can impact the timing and speed of the circuit, as well as the stability and performance of the circuit. It is important to consider the initial voltage of a capacitor when designing a circuit to ensure proper functioning and avoid potential problems such as voltage spikes or circuit failure.

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