Electric circuit symbols
Symbols
The following symbols show the different A device in an electric circuit, such as a battery, switch or lamp. that can be found in an electrical circuit.
Components
Some of the more common components are:
Switch
A switch is used to turn a circuit on (closed) and off (open).
Lamp
An electrical Moving electric charges, eg electrons moving through a metal wire. heats the A thin, high resistance wire that gets hot and glows when a current flows through it causing it to emit heat and light. Filaments are used in some types of bulb and electrical heaters. in a bulb so that it gives out light.
Fixed resistor
A resistor restricts or limits the flow of electrical current. A Electrical component with a resistance that is fixed and cannot be changed. has a The opposition in an electrical component to the movement of electrical charge through it. Resistance is measured in ohms. that does not change.
Variable resistor
Adjusting this resistor changes its resistance. A A resistor where the value of the resistance can be changed. is used in some dimmer switches and volume controls.
Thermistor
The resistance of a thermistor depends on its temperature. At low temperatures, the thermistor has a high resistance. As the temperature increases, the resistance decreases. A An electrical device whose resistance decreases as its temperature increases. can be used in thermostats or heat activated fire alarms.
Light-dependent resistor (LDR)
The resistance of a LDR depends on light intensity. At low light levels, the LDR has a high resistance. As the light intensity increases, the resistance decreases. A A Light Dependent Resistor is a type of resistor which is affected by changes in light levels. A cadmium sulphide layer causes a decrease in resistance in the light and increase in the dark. can be used as a sensor in cameras or automatic lights that come on when it gets dark.
Semiconductor diode
A Insulating material doped with impurities to affect electron energy bands and therefore affect conduction properties. An electrical device that allows current to flow in one direction only. allows current to flow in one direction only. Current will not flow in the other direction. Diodes are used to convert an Also called ac. An electric current that regularly changes its direction and size. into a Direct current is the movement of charge through a conductor in one direction only..