8)ELECTRONICS

Electronics involves the study of circuits and components that modify the intensity, direction or properties of electric currents.
ELECTRONIC COMPONENTS
In this section, we will analyse the most common electronic components.
FIXED RESISTANCE OR RESISTOR
A fixed resistance or resistor opposes the flow of electric current.Its value, which we meausre in ohms, is indicated by a code of colours and numbers.

The first two stripes are replaced by two numbers, according to their colour. The third stripe indicates the number of zeroes that we must add to the previous figure. The fourth stripe indicates the tolerance or the maximum deviation from the theoretical value.

VARIABLE RESISTANCE OR POTENTIOMETER

The value of a variable resistance or potentiometer can be adjusted between zero and the maximum value specified by the manufacturer.

RESISTANCE THAT DEPENDS ON A PHYSICAL FACTOR

The physical factrs that effect resistance may be temperature or the amount of light,for example.

• Resistance that depends on temperature is called a thermistor.There are two types of the thermistors:

          -Negative temperature coefficient(NTC):The resistance decreases as the temperature rises.

          -Positive temperature coefficient(PTC):The resistance increases as the temperature rises.

• LDR:Resistance that varies according to the amount of light received. The resistance decreass as the amount of light increases.These devices, like potentiometers, are often used in security systems, where they are parts of sensors.

CAPACITORS

Capacitors are components that can store an electrical charge.

The value of a capacitor indicates the charge in volts that it can store. This is measured in farads(F):

DIODES

A diode is an electronic component made from semiconductor materials.It only allows electric current to flow in one direction. A diode has two electrodes: An anode(A) and a cathode(K).

A LED(light emitting diode) only gives off light when an electric current flows through it.

For finish you can watch this video,surely it help you for understand: https://www.youtube.com/watch?v=JNi6WY7WKAI