Thevenin technique solving problem -- getting wrong answer

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In summary, the Thevenin technique is a method used to simplify complex electrical circuits for analysis and problem solving. It involves replacing the original circuit with a Thevenin equivalent circuit consisting of a voltage source and resistance. Some common mistakes when using this technique include forgetting to account for internal resistance, incorrectly identifying the open-circuit voltage, and not properly simplifying the circuit. If a wrong answer is obtained, it is important to double check calculations and simplify the circuit further. The Thevenin technique is most useful for analyzing circuits with multiple resistors and voltage sources, and for determining the maximum power that can be transferred from a circuit to a load.
  • #1
sciman
24
1
Hi

Can you tell me please what I am doing wrong here
upload_2015-4-15_16-15-57.png

I need to find the Vc function after we close the switch.
To do this, I calculate the Thevenin equivalent circuit.
I calculate Vth to be 21/(60+30) times 30, which makes 0.7V but why the answer is 7V?
Basically the answer is Vc=7x(... which means that final voltage of capacitor is 7V and not 0.7V.
Any idea?

thanks
 
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  • #2
Ehm hm, 30x(21/(60+30))=7
 
  • #3
I am embarassed
 
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What is the Thevenin technique?

The Thevenin technique is a method used to simplify complex electrical circuits into a single equivalent circuit for the purpose of analysis and problem solving.

How does the Thevenin technique work?

The Thevenin technique involves replacing the original circuit with a Thevenin equivalent circuit, which consists of a voltage source in series with a resistance. This equivalent circuit is then used to calculate the voltage and current in a specific part of the circuit.

What are the common mistakes when using the Thevenin technique?

Some common mistakes when using the Thevenin technique include forgetting to take into account internal resistance, incorrectly identifying the open-circuit voltage, and not properly simplifying the circuit before using the technique.

What should I do if I am getting a wrong answer when using the Thevenin technique?

If you are getting a wrong answer when using the Thevenin technique, double check your calculations and make sure you have properly identified the open-circuit voltage and internal resistance. If you are still getting an incorrect answer, try simplifying the circuit further or seeking assistance from a peer or instructor.

When is the Thevenin technique most useful?

The Thevenin technique is most useful when analyzing circuits with multiple resistors and voltage sources, as it simplifies the circuit and makes it easier to calculate voltage and current in specific parts. It is also useful for determining the maximum power that can be transferred from a circuit to a load.

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