Conductors Insulators

Key Concepts in Conductors and Insulators

Identification of Conductors and Insulators

• Conductors: Materials allowing movement of electrons and electrical current.

• Insulators: Materials resisting the flow of electrons and electrical current.

Conductive Materials

• Function: Free electrons allow for movement and current flow.

• Characteristics:

  • High electrical conductivity.

  • Generally have 1-3 valence electrons (e.g., copper, aluminium).

  • Metal examples: Copper (1 valence electron), Magnesium (2 valence electrons), Aluminium (3 valence electrons).

Semiconductor Materials

• Definition: Moderate electrical conductivity under certain conditions.

• Valence Electrons: 4 valence electrons (e.g., carbon, silicon, germanium).

  • Some electrons can break free at room temperature to conduct electricity.

• Applications: Used in transistors, diodes, solar cells, LEDs, lasers, and integrated circuits.

Insulator Characteristics

• Definition: Low electrical conductivity, few/no free electrons.

• Valence Electrons: Generally 5 or more; tightly bound to parent atoms.

• Common Insulators: Most nonmetals; requires significant energy to detach electrons.

• Usages: Prevent unwanted electric current; coat wires, separate electronic parts, prevent short circuits.

  • Examples include thermoplastics, glass, porcelain, and rubber.

Effects on Insulation Quality

• Factors Reducing Insulation:

  • Damage (cracks, splits).

  • Deterioration (aged materials).

  • Contamination (water, chemicals).

Electrical Cables Overview

• Types: Vary based on size, materials, and contexts (industrial, commercial, domestic).

• Long-Distance Transmission: Cables like 400 kV and 275 kV typically buried or suspended.

• Cable Components:

  • Conductors: Made usually of copper or aluminium (stranded or solid).

  • Insulation: Colored/number-coded for identification.

  • Protective Sheath: Outermost layer providing security (not always present in single-core cables).

Cable Construction Factors

• Determined By:

  • Working voltage (insulation thickness).

  • Current-carrying capacity (cross-sectional area of conductors).

  • Environmental conditions (mechanical protection and temperature requirements).