8. Electronics

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

8.1. Electric components.
-Fixed resistance or resistor.
A fixed resistance opposes the flow of electric currents. It's value, which we measure in ohms, is indicated by a code of colors and numbers.


-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 factors that affect resistance may be temperature or the amount of light, for example:

• Resistance that dependens on temperature is called a thermistor. There are two types of thermistor: NEGATIVE and Positive temperature coefficient.

LDR: Resistance that varies according to the amount of light received. The resistance decreases 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 componnents 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.


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 and a cathode.