Resistance and Ohms Law

Current flow can be thought of as 'how much' electricity is flowing around a circuit. Too high a current and you might damage the electronic components inside. Too little and they may not work as they have insufficient energy to 'power' them. Current is measured in 'Amperes' or 'Amps' (symbol big 'I').

Voltage is also known as 'potential difference'. It can be thought of as how much force there is 'pushing' the current around the circuit. If there is no potential difference between two electronic components in a circuit, then there can be no current flow. This means that voltage must be directly related to current flow. If one changes, then the other must also change. Voltage is measured in Volts (hence the name), It has the symbol big 'V'.

Finally, resistance can be thought of as a force trying to slow down the current flow. If resistance affects current, then because current and voltage are related then so must resistance affect voltage too.

This relationship is called Ohms law.

Everything I need to know about electronics

Electronics Club - An outstanding online resource for learning about all things electronics

Below is the embedded version of the 'electronics club' website. It is browse-able within the Cynffig D&T site but it is recommended to visit the site directly to view it how it was originally intended.

Electronics 'Cheat Sheets'

These handy 'cheat sheet' posters will help you recall important information such as:

• Ohm's Law

• Identify a resistor correctly

• Choose a suitable resistor to use with an LED

• Identify capacitors correctly

• Identify the correct pins on a 555 timer.....and more.

Click on them to view them in more detail.

Kitronic - How electronic principles guides

These fascinating guides explain how common electronic principles and popular components work.

Boolean Logic

PIC Microcontroller Projects

Project Ideas using an LM555 IC (or simply a 555 timer)