# A question with capacitor and a switch

• ursulan
In summary, the switch initially starts in position A with a 100V battery and an uncharged 15 microfarad capacitor (C1). When the switch is flipped to position B, the capacitors (C1, C2, and C3) are connected in series with C2 being 20 microfarads and C3 being 30 microfarads. The total capacitance is 6.66 microfarads and the charge on C2 and C3 is 667 microcoulombs. However, the charge on C1 is 833 microcoulombs, which may be due to the fact that it was initially charged before the switch was flipped.

## Homework Statement

Initially, the switch is in position A and capacitors and are uncharged. Then the switch is flipped to position B. Afterward, what are the charge on and the potential difference across each capacitor?

Position a is a 100V battery and a 15microF capacitor C1. Position B is C1 C2 and C3 in series with C2 being 20 microfarads and C3 30 microfarads.

Q=CV

## The Attempt at a Solution

I found the total capacitance which was 6.66uF, and the Q od C2 and C3 is 667uC which works for Q=CV. However Q1 is 833uF and I have no idea why! I know C in series all have same Q but C1 was charged first so i have no idea!

First, Farads are units of capacitance not charge.

i know i meant 833uC

## What is a capacitor?

A capacitor is an electronic component that stores electrical energy in the form of an electric field. It consists of two conductive plates separated by an insulating material, known as a dielectric.

## How does a capacitor work?

When a capacitor is connected to a voltage source, one plate becomes positively charged and the other becomes negatively charged. This creates an electric field between the plates, storing energy. When the capacitor is connected to a circuit, it releases this stored energy.

## What is the purpose of a capacitor in a circuit?

Capacitors can be used for various purposes in a circuit, such as filtering out unwanted frequencies, smoothing out power supply fluctuations, and storing energy to be released when needed.

## What happens when a switch is added to a circuit with a capacitor?

When a switch is added to a circuit with a capacitor, it allows the capacitor to charge or discharge as desired. When the switch is closed, the capacitor charges and when it is opened, the capacitor discharges.

## What is the time constant of a circuit with a capacitor and a switch?

The time constant of a circuit with a capacitor and a switch is the time it takes for the capacitor to charge or discharge to 63.2% of its maximum voltage or current. It is calculated by multiplying the capacitance of the capacitor with the resistance of the circuit.