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Electricity

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

Electricity

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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 received by an electrical device
- Electric power consumption by an electrical device
- Relationship between - Electric power and energy


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How to build simple circuits and draw diagrams

How to draw diagrams of electrical circuit ?

   
I1) Standard electric symbols

Each electrical component can be represented by a Standardized symbol.

Main standard electric symbols:


standard symbol for a bulb
Standard symbol for a bulb

standard symbol for a connection wire
Standard symbol for a connection wire

standard symbol for an open switch

                        Standard symbol for an open switch

standard symbol for a closed switch
Standard symbol for close switch

standard symbol for a battery
Standard symbol for a battery

standard symbol for an electrical motor
Standard symbol for a motor

standard symbol for a  resistor
Standard resistor for a resistor

standard symbol for a diode
Standard symbol for diode

standard symbol for a LED
Standard symbol for a LED


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2) Circuit diagrams

Circuit diagrams are drawn using standard symbols and following specific rules:
- 1) The diagram is drawn with a ruler and a pencil. Always begin by tracing its general shape that is a rectangle.
- 2) The standard symbols of the different electric components are located, preferably, in the middle of each side.
- 3) The order in which are placed the different symbols corresponds to the order of connection of components in the circuit.

Example of diagramming
The goal is to draw the diagram of the following circuit:

circuit to diagramming


First step:
We trace a rectangle with a ruler and apencil.

circuit diagram method step 1

Second step:
Each electrical component (battery, bulb and closed switch) is represented by its standard symbol in the middle of a side.
We begins by choosing three locations that are delete:

Circuit diagram method step 2


Then are placed the three symbols:

Circuit diagram method step 3


Comment: It is not necessary to add connection wires that are represented by the sides of the rectangle.

Step Three:
We check the order of connection. In the initial circuit, the positive terminal of the battery is connected to the bulb which is itself connected to the switch and the latter is connected to the negative terminal of the battery.
This order is respected in the diagram.

Comment: as long as the connection order is respected symbol can be placed on any side of the rectangle
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