Thevenin Equiv with just Capacitors

In summary, the question is asking how to find the Thevenin equivalent voltage given a voltage source and three capacitors in parallel. The attempt at a solution involves finding the equivalent capacitance and determining that half the voltage will be lost across the first capacitor. However, the given answer for Vth is 15V, which is less than the expected 22.5V. The conversation suggests that the problem may have been changed without the answer key being updated.
  • #1
kostoglotov
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Homework Statement



TWB5rRu.png


imgur link: http://i.imgur.com/TWB5rRu.png

Homework Equations

The Attempt at a Solution



I can find the equivalent capacitance, 10F, but I'm not really sure how to find the equiv. Thev. voltage. I figured that with the voltage source present, half the voltage will be lost across that first capacitor (since the next two parallel caps have an equivalence of 5F as well), so therefore at the very least in the Thev equiv circuit we should be seeing 22.5 V across the terminals. But the answer in the back gives Vth as 15V, less than 22.5.

How does one find the Vth?
 
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  • #2
Hmm. I wonder if at some point the problem was changed slightly without the answer key being updated. If the voltage source was 30 V rather than 45 V, then the given answer would make sense. I can't see the open circuit voltage being anything other than 22.5 V.
 
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Related to Thevenin Equiv with just Capacitors

1. What is Thevenin's theorem and how does it apply to circuits with just capacitors?

Thevenin's theorem states that any linear circuit can be simplified into an equivalent circuit with a single voltage source and a single resistor, known as the Thevenin equivalent circuit. This theorem also applies to circuits with just capacitors, where the Thevenin equivalent circuit would consist of a single capacitor and a single voltage source.

2. How do you calculate the Thevenin voltage and resistance for a circuit with just capacitors?

The Thevenin voltage can be calculated by finding the open-circuit voltage of the original circuit, while the Thevenin resistance can be found by taking the equivalent resistance of the original circuit when all voltage sources are replaced with short circuits.

3. Can Thevenin's theorem be used to analyze circuits with only capacitors?

Yes, Thevenin's theorem can be applied to any linear circuit, including those with just capacitors. It is a useful tool for simplifying complex circuits and analyzing their behavior.

4. Are there any limitations to using the Thevenin equivalent circuit for circuits with just capacitors?

The Thevenin equivalent circuit is only applicable for linear circuits, so it cannot be used for circuits with non-linear components such as diodes or transistors. Additionally, the Thevenin equivalent circuit is only accurate for DC circuits, as it does not take into account the effects of AC signals.

5. How does the Thevenin equivalent circuit help in circuit analysis?

The Thevenin equivalent circuit is a simplified version of a complex circuit, making it easier to analyze and understand the behavior of the circuit. It can also be used to determine the maximum power that can be transferred from the original circuit to a load connected to the Thevenin equivalent circuit.

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