Find peak voltage across capacitor

In summary, the conversation discusses a problem involving finding the peak voltage across a capacitor in a circuit connected to an AC battery and various lightbulbs. The only given information is the voltage of the battery and the resistance across two points. The person is unsure of how to approach the problem and is looking for guidance.
  • #1
randomdude20
2
0
Hi everyone!

I hope you people can help me out at a problem I am stuck with:

Homework Statement



Find the peak voltage across the capacitor "C"

All variables given and an image of the circuit are:

  • http://img36.imageshack.us/img36/580/photo2fsc.jpg [Broken]
  • The circuit is connected to an AC battery of 25V labeled as "U" in the diagram.
  • Lightbulbs "L1" and "L2" use 5.5 W each
  • Lightbulbs "L3" and "L4" use 2 W each
  • All bulbs will light up if they each receive 4.5V (thats exactly how the question states it)
  • Resistance across point "A" and "B" is 5.4 Ohm

2. The attempt at a solution

To be honest - I don't even know where to start this problem. The only thing which I thought to do is to calculate the peak voltage of the battery. Which is 35.36V. The next step I thought to do is to calculate the voltage across the bulbs - however I don't have any current value.

Any breadcrumbs to get me started would be great.
 
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  • #2
Do they give you the capacitance?
 
  • #3


I would approach this problem by first understanding the circuit and its components. From the given information, we know that the circuit is connected to an AC battery with a voltage of 25V and that the resistance across points A and B is 5.4 Ohm. We also know that all lightbulbs will light up if they each receive 4.5V.

To find the peak voltage across the capacitor, we can use the formula V = IR, where V is the voltage, I is the current, and R is the resistance. Since we do not have the current value, we can use Ohm's law to calculate it. Ohm's law states that current (I) is equal to voltage (V) divided by resistance (R).

In this case, the current can be calculated by dividing the voltage of the battery (25V) by the total resistance of the circuit, which is the sum of the resistance of the lightbulbs (5.5+5.5+2+2 = 15 Ohm) and the resistance across points A and B (5.4 Ohm). This gives us a total resistance of 20.4 Ohm. Therefore, the current (I) is 25V/20.4 Ohm = 1.23 A.

Now, we can use the formula V = IR to calculate the voltage across the capacitor. We know the current (1.23 A) and the resistance across points A and B (5.4 Ohm), so we can plug these values into the formula to get V = 1.23 A x 5.4 Ohm = 6.64V. This is the peak voltage across the capacitor.

I hope this helps guide you in solving the problem. Remember to always start by understanding the circuit and its components, and use relevant formulas and laws to solve for the unknown variable. Good luck!
 

1. What is a capacitor?

A capacitor is an electronic component that stores energy in an electric field. It consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied to a capacitor, it stores electrical charge on the plates.

2. How do you find the peak voltage across a capacitor?

To find the peak voltage across a capacitor, you can use a voltmeter or an oscilloscope. Connect the positive lead of the voltmeter to one end of the capacitor and the negative lead to the other end. The voltmeter will measure the voltage at the peak of the capacitor's charge cycle.

3. Why is it important to find the peak voltage across a capacitor?

It is important to find the peak voltage across a capacitor because it helps determine the maximum voltage that the capacitor can handle before it breaks down. This information is crucial in designing and using circuits to avoid damaging the capacitor.

4. What factors can affect the peak voltage across a capacitor?

The peak voltage across a capacitor can be affected by the capacitance, the applied voltage, and the frequency of the applied voltage. The capacitance determines how much charge the capacitor can store, while the applied voltage and frequency affect the rate at which the capacitor charges and discharges.

5. How can you calculate the peak voltage across a capacitor?

The peak voltage across a capacitor can be calculated using the formula V = Q/C, where V is the peak voltage, Q is the charge stored on the capacitor, and C is the capacitance. This formula assumes an ideal capacitor with no resistance or leakage. In real-world scenarios, the calculation may be more complex.

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