# 玩微信红包扫雷有猫腻

Science class online
Chemistry and physics lessons

# Electricity

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

 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

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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 connection wire standard symbol for an open switch                         standard symbol for a closed switch standard symbol for a battery standard symbol for an electrical motor standard symbol for a  resistor standard symbol for a diode standard symbol for a LED ______________________________________ ______________________________________ 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: First step: We trace a rectangle with a ruler and apencil. 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: Then are placed the three symbols: 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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