5.6 Capacitor Discharge Flashcards Preview

A-Level Physics EDEXCEL Year 2 > 5.6 Capacitor Discharge > Flashcards

Flashcards in 5.6 Capacitor Discharge Deck (11)
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1
Q

How do we know a capacitor has been fully discharged?

A

When pd across it is 0 and current in circuit is 0.

2
Q

What happens to charge and pd during discharge?

A

They both decrease exponentially.

3
Q

What happens to current during discharge?

A

Decreases exponentially.

4
Q

What happens during the discharge process?

A

1) The current flows in the opposite direction to charging.

2) Pd and current both decrease

5
Q

What is the equation for current during discharge?

A

It = (Io)e^-t/CR

6
Q

What is the equation for pd and charge during discharge?

A
Qt = Qo(1-e^-t/CR) 
Vt = Vo(1-e^-t/CR)
7
Q

Why does the current equation stay the same during charging and discharging?

A

As current always decreases when in a circuit with a capacitor.

8
Q

Why does a larger resistance in a circuit mean for the capacitor.

A

It will charge/discharge slower.

9
Q

In a Q/T graph how can we estimate the RC(time constant)?

A

We multiply max Q by 1/e (if discharge) or 1-1/e (for charge).

10
Q

What does the time taken for discharge/charge is affected by?

A

resistance and capacitance

11
Q

How do we discharge a capacitor?

A

Remove the power supply and completing the circuit.

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