Draw it with symbols
A circuit diagram shows a circuit using symbols.
A drawing shortcut
Drawing a cell, a switch and a lamp with all their details takes a long time. Electricians use a shortcut: one symbol for each part.
If you draw a circuit using only symbols for its parts, what do you think this drawing is called?
What this lesson covers
The idea
A representation of an electrical circuit using symbols for its components is called its circuit diagram.
A drawing shortcut
Drawing a cell, a switch and a lamp with all their details takes a long time. Electricians use a shortcut: one symbol for each part.
If you draw a circuit using only symbols for its parts, what do you think this drawing is called?
- A circuit diagram
- A circuit photograph
- A circuit map of the room
Picture to diagram
The picture on top shows a real circuit. Fill the gaps in the diagram with the right symbols.
A circuit diagram
The diagram has the same parts in the same order. Turn the switch ON in the picture or the diagram, and both show a closed circuit.
A representation of an electrical circuit using symbols for its components is called its circuit diagram.
Using the same symbols across the world helps people from different countries understand each other easily.
- Part | Symbol
- Electric cell | a long line and a short line
- Lamp | a circle with a cross
- Switch | a gap with a lever
- Wires | straight lines
Notes
A circuit diagram shows a circuit using symbols for its components.
Check yourself
What is a circuit diagram?
Why do we use symbols to draw circuits?
Which symbol stands for a lamp?
A diagram shows a cell, a switch and a lamp joined in a loop, with the switch ON. What does it tell you?
- A photograph of a circuit. A diagram uses symbols, not photographs.
- A representation of a circuit using symbols for its components — correct. Yes! That is what a circuit diagram is.
- A list of parts. A list names the parts but does not show how they are connected.
- They make circuits easier to draw and understand — correct. Yes! Symbols are quick to draw and read.
- They make the lamp glow brighter. A drawing cannot change how bright a real lamp is.
- They save electricity. A drawing does not use electricity.
- A circle with a cross — correct. Yes! This is the symbol of a lamp.
- A long line and a short line. That is the symbol of an electric cell.
- A triangle with a bar and two arrows. That is the symbol of an LED.
- The circuit is closed and current flows — correct. Yes! An ON switch closes the circuit.
- The circuit is open. An open circuit has the switch OFF.
- The lamp is fused. The diagram does not say that. It shows a closed loop.