Electricity: Standard Symbols

Circuit Symbols

In electrical diagrams, specific symbols represent different components. This “visual shorthand” makes it easier to understand and design circuits.
A cell is represented by a short line (positive) and a longer line (negative). This symbol can depict a single cell or a battery of cells.
The battery symbol consists of two or more cell symbols stacked together, indicating a battery pack.
The symbol for a lamp (light bulb) is a circle with a cross inside.
A resistor is represented by a zig-zag line.
Switches have two main symbols: If the switch is closed (on), it’s depicted as two lines connected by a line. For an open (off) switch, the connecting line is broken.
A fuse symbol looks like a resistor, but with an ‘S’ shape rather than a zigzag.
A diode is represented by a triangle pointing towards a line. Current can flow in the direction of the triangle.
A LED (Light Emitting Diode) has the same symbol as a regular diode, but with two arrows pointing outwards to indicate light emission.
The symbol for a capacitor consists of two parallel lines - these represent the plates of a capacitor. A straight line denotes a direct current (DC) capacitor, while a curved and straight line represent an alternating current (AC) capacitor.

Measuring Instruments

An Ammeter measures current and has a symbol that resembles an ‘A’ within a circle.
A voltmeter measures voltage and has a symbol that looks like a ‘V’ within a circle.

Remember that knowing these symbols will enable you to quickly comprehend and construct electrical diagrams. It also ensures your work is understood universally, as these symbols are standard across the globe.