Fundamentals of Electrical Materials and Components

Electrical Material Basics

Conductors: Materials that allow electrons to pass through them easily.

Insulators: Materials that prevent the passage of electrons. Examples include plastic, wood, ceramic, concrete, and stones.

Introduction to Electronics

Electronics is the branch of physics that studies the control of electron movement in semiconducting materials. Under normal conditions, these materials act as insulators. However, when certain factors are changed (such as electric fields, magnetic fields, or pressure), they become conductors. The most common semiconducting materials are silicon and germanium. Electronic circuits are primarily used to control and distribute information and have been crucial to progress in computing.

Key Electronic Components

1. Resistor

   A resistor limits the flow of electrical current through a circuit. Most common resistors are made from carbon. The value of a resistor can be determined by the coloured rings on it. A resistor typically has four coloured bands; the last band is generally gold or silver.

2. Potentiometer

   This is a variable resistor. Its resistance value changes from 0 Ω to a maximum value by manually rotating a wiper. This action effectively converts the component's behavior between that of a conductor and an insulator.

3. Photoresistor (LDR)

   This is a variable resistor whose resistance depends on the light emitted onto it. When the LDR receives light, its resistance decreases, causing it to act as a conductor. When the LDR does not receive light, its resistance increases, causing it to act as an insulator.

4. NTC or Thermoresistor

   This is a variable resistor whose resistance changes depending on the temperature. When the NTC is heated (e.g., to 40ºC), its resistance decreases, and it acts as a conductor. When the NTC is frozen, its resistance increases, and it acts as an insulator.

5. 7-Segment Display (LEDs)

   This is a display screen used for showing information using decimal numbers. It is commonly found in calculators, digital clocks, etc.

6. Relays

   A relay is a switch controlled by an electromagnet. It is used to open or close electrical contacts.

7. Diode

   When the positive terminal (+) of the diode is connected to the positive terminal (+) of a battery, the diode acts as a conductor. When the positive terminal (+) of the diode is connected to the negative terminal (-) of the battery, the diode acts as an insulator.