Current Flowing Through RC Circuit (Charging)

In summary, there is a debate about the current through resistors 1 and 2 in a circuit with a closed switch and initially open switch. The friend thinks the current through R1 is zero while the expert thinks it is non-zero due to the need to charge the capacitor. The current through R2 is agreed to be non-zero. Another question about the voltage drop across C2 and C3 is raised, and the expert explains that the voltage across the resistor and capacitor must be zero, resulting in zero current according to Ohm's law.
  • #1
AnXioZ
4
0
Hey, everyone. Just a quick question here. If I have the following circuit, with it's switch initially opened, what will happen to the current through resistors 1 and 2, after I close the switch?

http://img249.imageshack.us/img249/7716/showmeplkh6.gif

1) When the switch is first closed, the magnitude of the current through R1 is ______ and the magnitude of the current through R2 is ______.

My answer is: non-zero, non-zero

My friend thinks: zero, non-zero

Now, we are having a debate over this question. We both agree that the current through R2 is definitely non-zero; however we disagree on the current through R1.

I think that there should be current through R1 because the capacitor has to get charged somehow.

What do you think?

Thanx in advance.
 
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  • #2
whats the voltage drop through c2 and c3 at that time?
 
  • #3
Thank you for your question granpa :D !

You have to think of the resistor R1 as a resistor who is connected in parallel to Capacitor C2,3. Therefore the voltage across the resistor and the capacitor, immediately after the switch is closed, must be zero.

Gotta love physics <3
 
  • #4
AnXioZ said:
Therefore the voltage across the resistor and the capacitor, immediately after the switch is closed, must be zero.
Then by Ohms law what is the current if the voltage is zero?
 

1. What is an RC circuit?

An RC circuit is a circuit that contains both a resistor (R) and a capacitor (C). It is commonly used in electronic devices to control the flow of electric current.

2. How does a capacitor charge in an RC circuit?

When a voltage source is connected to an RC circuit, the capacitor starts to charge. Initially, the capacitor has no charge and acts as a short circuit, allowing the maximum amount of current to flow through the circuit. As the capacitor charges, it acts as an open circuit, limiting the flow of current.

3. What is the equation for current in an RC circuit during charging?

The equation for current (I) in an RC circuit during charging is I = V/R * (1 - e^(-t/RC)), where V is the applied voltage, R is the resistance, t is time, and C is the capacitance.

4. How does the current in an RC circuit change over time during charging?

At the start, the current is at its maximum value, and as the capacitor charges, the current decreases. Eventually, the current reaches zero, and the capacitor is fully charged. The current gradually decreases according to an exponential decay function.

5. What happens to the current in an RC circuit after the capacitor is fully charged?

Once the capacitor is fully charged, the current in the circuit becomes zero, and the capacitor acts as an open circuit, blocking any further flow of current. The capacitor will continue to hold its charge until it is discharged or the circuit is broken.

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