# Electricity

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Free online electricity lessons for elementary school,  middle school and high school.

## Basic electronical components

1) Batteries and electric generators
In a circuit, the role of battery is to produce an electric current.
There are various kinds of batteries: round, flat batteries, button cells ...
However, all batteries have two terminals:
- A positive terminal marked with the symbol +
- A negative terminal marked with the symbol -

Like batteries, electric generators produce an electric current.
Nevertheless electric generators use mechanical energy whereas batteries use chemical energy.

Example of electric generators: dynamos, alternators in power plants and wind turbines.
Comment: Solar panels may also produce an electric current by using solar energy.

An electrical component that may produce electric current is said to be an " active component "
It is considered that other components are " passive components "
A passive component therefore receives the electric current but doesn't produce it.
Examples of passive components: bulbs switches, motors.

2) Bulbs

Bulb are two-terminal components.
They produce light thanks to their filament made ​​of a metal (tungsten) that is heated under the effect of the current until it becomes incandescent.

3) Switches

A switch is used to control the operation of a circuit. For this electricity lesson, we use only toggle switches or push button switches, but there are many other models of varying complexity (magnetic, electronic, etc.)

4) Material to realize a connection

Making a connection means connect a two-terminal component to another so that current can flow between them.

In an electrical device, two-terminal components are interconnected with electrical wires and solders.

For these electricity lessons, we use connection wires whose ends consist of banana plugs.
They are designed to be connected to the banana sockets.

- Connection of flat batteries.
The flat batteries have no banana sockets therefore, to connect them, we must use alligator clips that can be placed on banana plugs.

- Connection of bulbs.
Bulbs haven't banana sockets. They are fixed by screwing on a support. This support has two terminals consisting of banana sockets connected to lamp terminals.

This support system is also used for other two-terminal components which do not have a banana sockets

 Science class Chemistry Electricity Optics Mechanics Electricity lessons Electrical components -Two-terminal electronic components - Basic electrical components - Diodes - What's a resistor ? - How to determine a resistor value ? - Resistors effects in circuits - How to use a resistor ? - Characteristic curve of a resistor How to build simple circuits and draw diagrams - How to build a basic electrical circuit - How to draw diagrams of electric circuits The electric current - Conductors and insulators - Direction of electric current in a circuit - The dangers of electricity - Current intensity - units how to measure current ? The Voltage - The voltage and its units - How to measure a voltage ? - Voltage in open and closed circuits - Rated current and voltage for a lamp Alternating voltage and current - Alternating currents effects on led - What are alternating current and voltage ? - Periodic alternating voltage and its properties - Oscilloscope - Oscillogram - Frequency - Measuring RMS voltage with a voltmeter Serie circuits - What's a serie circuit ? - Series circuit properties - Short circuit in  series circuit - Current law in series - circuits - Voltage law in series circuits Parallel circuits - What's a parallel circuit ? - Some parallel circuits properties - Short circuits in parallel circuits - Nodes and branches in parallel circuits - Current laws in parallel circuits - Voltage laws in parallel circuits Laws of electricity - Ohm's law - Current laws in series circuits - Voltage laws in series circuits - Current laws in parallel circuits - Voltage laws in parallel circuits Generating electricity - Voltage for coil wires What is an alternator ? - Alternating currents and voltages - Generating electricity in power plants Electric power and energy - Electric power and power rating - Electric power consumption by an electrical device - Relationship between - Electric power and energy