LESSON 6  -  CIRCUIT DIAGRAMS

The different types of components we have encountered each have a symbol to represent them in a circuit diagram. A circuit diagram is just a picture of how all the components in a circuit are connected together.

Here are the symbols for the components we have met:

	wire
	join
	resistor
	preset - the arrow represents the wiper
	non-electrolytic capacitor
	electrolytic capacitor - the black line represents the negative plate
	LED - the arrow shows the direction that conventional current can flow (electrons actually flow in the opposite direction!)
	transistor - the arrow shows the direction that conventional current flows
	piezo speaker (there is no standard symbol for a piezo)
	battery

Here is a complete circuit diagram. Don't worry about what the circuit does (it just lights up the LED) but notice the fact that you can trace a continuous route from the battery through the resistor and LED and back to the battery, i.e. it is a circuit.