BASIC DEVICES MADE WITH ELECTRONIC COMPONENTS

1.Timers
It is a device that operates for a certain period of time and then shuts itself off automatically:


-At first, the LED is off,since there is no current flowing through the base. When we push the button, current flows through the base , and the transistor is activated, and the LED turns on. The capacitor also begins to charge itself.


-When we release the button, the LED continues to produce ligh for some time, using current from the capacitor.

2.Integrated circuits
They consist of miniature electronic components.

                             

ELECTRONICS III

Transistors
They are basic components of electrical circuits. They are made from semiconductor materials and have three electrodes: the base, the collector and the emitter.
There are two types of transistor: NPN and PNP.

• When no electrons are flowing through the base, it is in cut off.
• When many electrons are flowing through the base, it is in saturation.
• When the flow of electrons through the base is between the cut off and saturation levels, it is in the active region.

ELECTRONICS II

-Capacitors
They can store electrical energy from a battery and then use it to power a light bulb until the charge is totally depleted. This is measured in farads.

-Diodes

They are electronic components made from semiconductor materials. A diode has two electrodes: an anode and a cathode.

A LED only gives off light when an electric current flows through it.

ELECTRONICS I

-Fixed resistance or resistor
It opposes the flow of electric currents. Its value is indicated by this code of colours and numbers:

-Variable resistance or potentiometer

Its value can be adjusted between zero and the maximum value specified by the manufacturer.

-Resistance that depends on a physical factor

• Resistance that depends on temperatura is called termistor. There are two types: negative and positive.
• LDR: resistance that varies according to the amount of light received.