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Q&A Voltage and Current of capacitor

After the switch is closed: The general formula for finding the voltage of the capacitor is: where Vf is the voltage of the inductor after infinite time,Vo is the voltage of the capacitor at ...

posted 3y ago by MissMulan‭

Answer
#1: Initial revision by user avatar MissMulan‭ · 2021-09-03T14:04:35Z (over 3 years ago)
After the switch is closed:

![hi](https://electrical.codidact.com/uploads/uLJ6gVBb2aFiTWMGQWQvaDoy)

The general formula for finding the voltage of the capacitor is:

![hi](https://electrical.codidact.com/uploads/R72N8N5VdczqdpzyVoohHs5k)

where Vf is the voltage of the inductor after infinite time,Vo is the voltage of the capacitor at the time the switch is closed

Because capacitors resist any change in voltage


![hi](https://electrical.codidact.com/uploads/UagX5iBcnJAqVDTsA7wW8Ahg)

This tells us that at the moment the switch is closed the voltage of the capacitor will be equal to its voltage before the switch is closed whichcis equal to 0.

![hi](https://electrical.codidact.com/uploads/DSvjNJrJSK1TWnHhSMXCxtTd)

As t tends to infinity the inductor will act as a open circuit which means that by voltage division the voltage will be 0.88V

the R in the exponent is the total resistance seen by the capacitor which is:

![hi](https://electrical.codidact.com/uploads/QtWjmGvnrRUzxgu9ZTuQJyoH)

so the voltage of the capacitor equation will be:

![hi](https://electrical.codidact.com/uploads/AAtx5FQWi5sPRTq7h285zrFb)

and the current through the capacitor will be:

![hi](https://electrical.codidact.com/uploads/ygaFiEWG7whLHa6pnxHRxYSm)