Why do capacitors dis/charge suddenly and then slow down?

Capacitors are made up of two plates (& so the symbol) which you can imagine as 'boxes' of opposite polarity and are seperated with insulation. 

As capacitors charge, the negative box keeps filling with electrons while the other (positive) box loses any electrons still in them due to repulsion from this negative box. Since the negative box is relatively empty to start with, electrons fill in very quickly. As their numbers increase, the capacity of the box reduces and the electrons repel any new electrons coming in, which slows the flow of electrons. 

Similarly for capacitor discharging, the now filled negative box easily looses its electrons to the empty positive box very quickly. But as their numbers start to even out, the flow slows down. Hence, the graphs potray an exponential relationship for capacitors when charging and discharging takes place. 

This is quite similar to you filling/emptying a balloon with water; it starts to fill/empty very suddenly at the beginning but slows down over a period of time. .

SB
Answered by Shail B. Physics tutor

19658 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Explain the workings of a mass spectrometer


If a ball of mass 5kg is dropped from rest, how far will it travel in the 3 seconds after it reaches 150m from it's original position? Write down the change in it's total energy after the 3 seconds. (ignoring air resistance)


A railway car of mass m1 travelling at a velocity of v1 collides with a second car of mass m2 travelling at v2 and the two join together. What is their final velocity?


Describe the photoelectric effect.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences