Capacitors

What is the definition of capacitance?

Capacitance is the amount of charge stored per unit of pd

What is the unit for capacitance?

The Farad

How can we explain the charging of a capacitor?

Electrons will flow from the negative terminal of the cell to the negative terminal of the capacitor. The excess electrons on the negative plate are going to repel electrons off the positive plate of the capacitor, which will move towards the positive terminal of the cell. Overall, the plates will acquire an equal and opposite charge

How can we explain the discharging of a capacitor?

When a capacitor is connected to a circuit, the excess electrons are going to flow from the negative plate to the positive plate. The charge on the capacitor decreases.

In a parallel circuit, the voltage is…

The same across each parallel branch of the circuit

In a parallel circuit the charge is…

Shared, as current is shared

In a series circuit, each capacitor will experience…

The same current, so it will acquire the same charge

In a series circuit the p.d. is…

Shared by Kirchhoffs 2nd law

When a capacitor is discharging, the voltage…

Decreases exponentially

Other than voltage, which factors decrease exponentially as a capacitor discharges?

The charge and the current

The charging/discharging of a capacitor depends on…

The resistance and the capacitance

What is the definition of the time constant?

At time t = time constant, the pd, the charge and the current drop to 37% of their initial value