Science class online
Chemistry and physics lessons
atom physics lesson

Electricity

Free online electricity lessons for elementary school,  middle school and high school.
chemistry 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 received by an electrical device
- Electric power consumption by an electrical device
- Relationship between - Electric power and energy


_____________________________________________________
 
_____________________________________________________
 

The electric current

Current and units

   
1) Effect of current

In a series circuit consisting of a variable voltage generator and a bulb, the brightness of the bulb is stronger when the voltage supplied by the generator is higher: the current is therefore also higher

The higher current received by an electric component is, the more efficient this component is.

2) Units

Current is always denoted with symbol I
It is measured in ampere (symbol A) with a device called ammeter

Comment: you can also use units derived from ampere as kiloampere, hectoampere the decaampere the deciampere etc.
The most widely used of these derived units is milliampere symbol mA (1 A = 1000 mA)

Example: If a current of 0.5 amperes flows through a bulb then we can write:
I = 0.5 A
or
I = 500 mA
______________________________________


______________________________________


 


____________________________________


____________________________________