Summary AQA AS/A Level Physics A* Revision Notes: Capacitors 2.

Capacitors FINALLY understood!

Watch: https://www.youtube.com/watch?v=wCtS2SPg8Ik

Capacitance in series?
~remember: the opposite to resistance~
- 1/Ctotal = 1/C1 + 1/C2




Capacitance in parallel?
~remember: the opposite to resistance~
- Ctotal = C1 + C2




Why is the rate of charging of a capacitor slowing down over time?



Rearrange the capacitor discharging equation (for charge Q)?
https://www.youtube.com/watch?v=wCtS2SPg8Ik
What happens at the time constant when a capacitor discharges?




Question from 15:05?
https://www.youtube.com/watch?v=wCtS2SPg8Ik
Why does the rate of change of pd between the capacitor plates decreases as the
capacitor discharges?
- V is proportional to Q
⇒ the rate of change of Q is proportional to the rate of change of V
- rate of change of Q (rate of flow of charge/electrons) = current
- current decreases

, OR



Adv.s of analogue ammeters over digital? (despite digital being obvs better wth??)
- position on scale can be marked
- easier to read quickly
Full scale deflection current meaning?
~for an ammeter~
- the max current an ammeter can measure
→ in the case of capacitors, it’s usually 100 or 200 microAmps

Practical: Investigate the charging of a capacitor