Electrical circuits

Introduction

A circuit is required in order for electricity to flow. A circuit is a closed, never-ending loop of conductive material (conductive materials have a loose hold on their electrons allowing them to conduct electricity and heat). Circuits come in varying shapes and sizes with the most basic one as simple as a conductive wire connected end-to-end. The only rule when it comes to making circuits is they can’t have any insulating gaps in them.

Main components

• Resistors
• Capacitors
• LED
• Transistors
• Inductors
• Cells and batteries
• Switches
Resistors:

Resistors are represented by this symbol:



Resistors control the flow of current to other components.



Capacitors:

Capacitors are represented by this symbol:



Capacitors store electric charge. As electric charge flows to the capacitor it fills up and once full releases the charge, therefore holding for a second. The purpose of a capacitor is to time electronic switching. The time on, and time off are set by the capacitor and two resistors.



LED's:

LED’s are represented by this symbol:



A LED is a light-emitting diode and converts electrical energy into light energy.



Transistors:

Transistors are represented by this symbol:



Transistors are semiconducting devices which are used to amplify or switch electronic signal. A transistor is able to amplify, as its output can be much bigger than its input.



Inductors:

Inductors are represented by this symbol:



Inductors are electrical components, which are able to store energy from a circuit in a magnetic field. The wire (shaped as a coil) creates a magnetic field as the current passes through it. Inductors are used to limit the build-up of alternating current, which is an electric current that reverses its direction many times a second at regular intervals, in a circuit. An inductors can also keep the circuit running when the supply is switched off.



Cells and batteries:

Cells are represented by this symbol:



Batteries are represented by this symbol:



A battery is a source of energy used to power a circuit, whilst a cell is a single unit of power capable of supplying energy.



Switches:

Switches are represented by this symbol:



A switch controls the flow of current within a circuit. Switches can only be opened or closed, meaning they are binary. An open switch disallows the flow of current, whilst a closed switch allows the flow of current.



Connectors:

Connectors are represented by this symbol:



Connectors connect all the components of the circuit and create path for electricity to pass through. Connectors are generally metal wires with a plastic coating.



Buzzer/bell:

A buzzer is represented by this symbol:



A buzzer (otherwise known as a beeper) makes a buzzing or beeping noise. A buzzer converts electrical energy into sound energy.