Circuit Symbols Trivia Quiz

This symbol is used to denote a switch. Specifically, it is a single pole, single throw switch which means there is one input which connects to only one output. The symbol is used in this position for a switch which is normally open, i.e. normally in the off position.

This symbol can be augmented with many other details to give more information about the type of switch such as whether it has delayed operation, is on a timer, is connected to an electric motor and many more.

This symbol is used for a single cell battery. It is customary to include the plus and minus signs to show the positive and negative terminals of the cell but it is not strictly necessary as the longer plate is always used to denote the positive terminal. If a battery contains more than one electrical cell the symbol is used multiple times together to represent the cells in the battery.

An ammeter is a device used to measure the electric current in a circuit. The device name is a shortening of ampere meter after the ampere - the unit in which electric current is measured. Ammeters can be used in circuits temporarily for testing or be more permanent fixtures used for monitoring the current in systems.

The symbol for an ammeter is a circle containing a letter A, a similar symbol with the letter V in it is used to show a voltmeter.

This is the symbol for a diode, which is a component that only allows current to flow in one direction. Because of this it has to be included the correct way round in circuits otherwise the current will not be able to flow as expected. The current flows through the diode from the anode (at the bottom of the triangle portion) to the cathode (at the line across the top of the triangle).

A capacitor is a device used to temporarily store electrical charge in a circuit and can usually discharge the accumulated charge relatively quickly. The symbol here shows a polarised capacitor, meaning it has a positive and negative pole and thus must be connected the correct way round in the circuit; the positive pole of the capacitor is denoted with the plus sign. If the symbol was for a non-polarised capacitor then it would not include the plus sign.

This is the symbol for a fuse. A fuse is a safety device for a circuit and usually consists of a thin wire inside a glass or ceramic case. The wire is designed to melt if the current exceeds a safe value thus breaking the circuit and stopping the flow of current. Fuses are used in many applications to protect electrical equipment.

In the UK most household appliances have a fuse included in the plug which is designed to protect the appliance in case of a surge of current.

Transistors are a type of semiconductor device and are usually made from silicon. They are used to switch or amplify electrical signals. The component often referred to as a microchip, or simply just as a chip, is actually made up of many miniature transistors working in harmony to produce the desired effect. Transistors are found in almost all modern electrical equipment and were a key invention of the 20th century helping to fuel the computer revolution of the late 20th century.

This is the symbol for a light-emitting diode or LED as it is commonly known. An LED is a special type of diode (you might notice that the symbol is very similar to that of the diode) that glows when connected to an electrical circuit. LEDs generally use less power, and have a longer lifespan, than traditional bulbs and have commonly been used for small indicator lights (e.g. to show if something is switched on or not).

As the technology has been improved LEDs are now commonly replacing traditional incandescent light bulbs as a lower energy alternative.

A resistor is a component designed to reduce the current flow in a circuit. Resistance is measured using Ohms which is represented by the Greek letter Omega. Resistors usually have coloured stripes on them which correspond to a special code and enables the user to be able to tell what level of resistance is offered by that resistor.

This is the symbol for a lamp and is often used to represent the location of a small light bulb in a circuit. Technically this symbol should only be used when the bulb is being used as an indicator, for example showing when a component is switched on or off, rather than for a bulb being used for lighting purposes.

The symbol for a lamp being used for lightning is a circle with a line with a slight hump running through it.