Sound

We can transform electric current into sound by using electromechanical devices, such as bell and buzzers. Some of these devices are based on the piezoelectric effect, or the ability of some materials to change shape when electricity is applied to them.

Electromagnetic Effects

In this experiment, the elctric circuit has created a magnetic field. This effect can be used to produce movement.
The scientist Michael Faraday discovered the opposite effect. He notice that electricity could be generated by using a magnet and an electrical conductor. This priciple allows us to build dynamos and alternators.

Light

Incandescent bulbs

When an electric current passes throught the metallic filament of a light bulb, it produces light. This phenomenon is called incandescence.






Fluorencent tubes


Inside a fluorencent tube, there is a metallic filamen, normally made of tungdten. There is also an inert gas, such as argon, and a small amount of mercury.



Light- emitting diodes (LED)

A light-emitting diode (LED) has layers of semiconductor materials.When electricity is applied to the LED, the electrons and holes cross over into the active layer, where they combine and produce photons, or particles.

Heat

The energy that an electric current produces as heat is called the Joule Effect. It is expressed by the following formula:

E = I^2 x R x t

Most of the energy that is consumed by radiators and heaters is converted into heat.

Transformers

Transformers consist of two windings made of cooper wire. If we apply an alternating current to one of them (V1), It will produce a certain voltage in the other (V2) The value will depend on the number of times that the cooper wire has been wrapped around each winding, represented as n1 and n2:

V1 / V2 = n1 / n2

The effinciency of alternating current

The average power of alternating current is equal to the direct current that is needed to produce the same effect. In the case of an alternating sinusoidal current, the average power would be as follow.

Vef = Vmax / 1,41

Alternating current

The variation of any electrical parameter over a period of time is an electric signal.

The tension or voltage of domestic electricity is an alternating signal because it alternates between positive and negative values. Its waveform is also sinusoidal, with a smooth, regular shape.

Direct current

Between the terminals of a battery, there is a continuous, stable flow of energy

                                                       .