Categories of Materials in Electronics
In electronics, materials are broadly classified into three categories: conductors, semiconductors, and insulators.
Conductors
Conductors are materials that readily allow the flow of electric current. They possess a large number of free electrons and typically have one to three valence electrons in their atomic structure. Most metals fall into this category, with silver being the best conductor and copper being widely used due to its cost-effectiveness. Copper wire is commonly employed in electrical circuits.
Semiconductors
Semiconductors have fewer free electrons compared to conductors, limiting their ability to carry current. They have four valence electrons in their atomic structure. Despite their reduced conductivity, certain semiconductor materials, such as silicon and germanium, are fundamental to electronic devices like diodes, transistors, and integrated circuits.
Insulators
Insulators are nonmetallic materials with poor conductivity, effectively resisting the flow of electric current. They lack free electrons in their structure, and their valence electrons are tightly bound to the nucleus. While nonmetal elements are generally considered insulators, practical insulators in electrical and electronic applications include compounds like glass, porcelain, Teflon, and polyethylene.
ELECTRICAL CHARGE
The charge of an electron is equal in magnitude and opposite in sign to that of a proton. Electrical charge, symbolized by Q, is a property of matter resulting from an excess or deficiency of electrons. Static electricity, characterized by a net positive or negative charge in a material, is a common phenomenon experienced in everyday situations, such as when clothes cling together in a dryer. Oppositely charged materials attract each other, while materials with the same charge repel each other. This attraction or repulsion is governed by an electric field, represented by invisible lines of force.