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Chemistry

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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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Electrical components

Characteristic curve of a resistor

   
1) What is a characteristic curve ?

Definition: A characteristic curve is the graph on which are represented the variations in the voltage at the terminals of a component as a function of the current passing through it.

2) How to draw the characteristic curve of a resistor ?

To draw the characteristic curve of resistor we need the following circuit:

electric circuit used to draw the characteristic curve of a resistor

This circuit consists of a battery providing a variable voltage, a resistor, an ammeter and a voltmeter.
If the voltage of the battery changes there is a variation of voltage for the resistor and also a variation of electric current.
The measuring instruments are used to determine several couples of values ​​(voltage and current).
These couples are the coordinates of points used to draw the characteristic curve on a graph with the current on abscissa axis(horizontal axis) and the voltage on ordinate axis (vertical axis).
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3) Properties of the characteristic curve of a resistor


The characteristic curve of a resistor is always a line passing through the origin point.
This line indicates that the voltage of the resistor is proportional to the current.
The proportionality coefficient corresponds to the resistance.
example:
For a 10 ohm resistor we obtain, thanks to the measures, the following points:
(I = 0.1 A, U = 1 V), (I = 0.2 A, U = 2 V), (I = 0.3 A, U = 3 V)
(I = 0.4 A, U = 4 V) etc.
These values ​​are used to draw the following graph:

Characteristic curve of a resistor

The voltage is ten time greater than current: ten is also the resistance.
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