BASIC DEVICES MADE WITH ELECTRONIC COMPONENTS

We can build various devices with the electronic components discussed in the previous section. Here are two examples:
Timers.
 A timer is a device thet operates for a certain period of time and then shuts itself off automatically.

Integrated circuits.
Integrated circuits consist of miniature electronic components, such as transistors, resistors and capacitors.

ELECTRONIC COMPONENTS

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

-When no electrons are flowing through the base, then no electrons can pass from the collector to the emitter. The transistor is in cut off.

- When many electrons are flowing through the base, the route between the collector and the emitter will be completely open. The transistor is in saturation.

- When the flow of electrons through the base is between the cut off and saturation levels, it will be proportional to the flow of electrons between the collector and the emitter. The transistor is in the active region.

ELECTRONIC COMPONENTS

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

ELECTRONIC COMPONENTS

Resistance that depends on a physical factor.
- Resistance that depends on temperature is called a thermistor.
There are two types of 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 decreases as the amount of light increases.

ELECTRONIC COMPONENTS

 Fixed resistance or resistor
A fixed resistance or resistor opposes the flow of electric currents. 
Its value, which we measure 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

 POTENTIOMETER.

                                

ELECTRONICS

Electronics involves the study of circuits and components that modify the intensity, direction or properties of electric currents.