You are Here: Home >< GCSEs

# GCSE Physics watch

1. Can someone explain how a dynamo works.
2. (Original post by *Alisha*)
Can someone explain how a dynamo works.
I can't remember how much you need to know at GCSE, you might have better luck on Bitesize or something.
The essence of how a dynamo works is that according to Faraday's law, a varying magnetic field induces an electromotive force (e.m.f) (another term for potential difference or a voltage if you will) in a closed circuit.
The strength of this effect depends on how fast the field varies, how many coils your wire has and the strength of the field itself.
In a dynamo a coil of wire is rotated inside a fixed magnetic field, relative to the wire the field then varies and so an e.m.f is induced.
A dynamo usually has a commutator to ensure a more useful direct current output is generated rather than the AC output that would otherwise occur, essentially half way through the rotation the connection of the wires is reversed meaning that the output is still DC, a better explanation can be found here.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 29, 2016
Today on TSR

### Three reasons you may feel demotivated right now

...and how to stay positive

### Can I get A*s if I start revising now?

Discussions on TSR

• Latest
Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE