MYTUTOR SUBJECT ANSWERS

507 views

How do capacitors work and what are its units?

Capacitors are an electrical component made up of two plates with an insulator between them.

Electrons flow onto one of these plates as current flows around the circuit. This gives one of the plates a negative charge. 

As electrons build up on this plate, they repel electrons positioned on the plate opposite (negative-negative repulsion). 

This gives the other plate a positive charge. For each electron flowing onto the first plate, one is repelled on the plate opposite. This gives the plates an equal and opposite charge.

NO current flows through the capacitor, charge simply accumulates on each of the plates. This accumulation of charge is effectively stored energy. Electrons will continue to flow onto the negative plate until such a time as the negative plate repels electrons. This means the potential difference across the plates is equal to the emf of the power supply. 

Each capacitor varies with how many charges its plates can hold, and thus how much potential difference can exist across the plates. This ratio of charge stored to the maximum potential difference between plates is defined as the capacitance. It has units F (the farad, after Faraday). One farad is equal to one coulomb per volt, so one farad is a very large quanitity! Usually capacitors have values of the order millifarad or microfarad. 

Matthew  B. A Level Physics tutor, GCSE Physics tutor, A Level Maths ...

1 year ago

Answered by Matthew , an A Level Physics tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

75 SUBJECT SPECIALISTS

£36 /hr

Duncan L.

Degree: MPhys Physics with Study in Australia (Masters) - Exeter University

Subjects offered:Physics, Maths+ 1 more

Physics
Maths
-Personal Statements-

“I am a third year physicist at Exeter, I love my course and I am keen to share my knowledge and experience to help you with GCSE and A level maths and physics.”

£20 /hr

Daniel O.

Degree: Natural Sciences (Masters) - Nottingham University

Subjects offered:Physics, Maths+ 1 more

Physics
Maths
Chemistry

“An enthusiastic Natural Sciences undergraduate at the University of Nottingham with industry experience working for the Defence Science Technology Laboratories.”

Timothy N. A Level Design & Technology tutor, GCSE Design & Technolog...
£26 /hr

Timothy N.

Degree: Architecture and Environmental Engineering (Masters) - Nottingham University

Subjects offered:Physics, Science+ 3 more

Physics
Science
Maths
Design & Technology
-Personal Statements-

“Hi there, I have a passion for helping students achieve, and believe that with my years of experience tutoring, we will be able to surpass the grades you want!”

About the author

£20 /hr

Matthew B.

Degree: Physics (Masters) - Warwick University

Subjects offered:Physics, Maths

Physics
Maths

“About Me:  I am a physics undergraduate at the University of Warwick. I have always been interested in science and curious about the world around us; I am passionate about education andlearning new things. It is my aim to help you bec...”

MyTutor guarantee

You may also like...

Posts by Matthew

How do capacitors work and what are its units?

What is Olbers' Paradox?

What is the 'centre of gravity' of an object and how do I calculate it?

Other A Level Physics questions

Explain in terms of the motion of the molecules of the gas why the volume of gas must increase if the pressure is to remain constant as the gas is heated.

How can an object be accelerating when it's velocity is constant, and how does centripetal acceleration work.

Define electrical resistance

What is the main evidence for the Big Bang theory?

View A Level Physics tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok