Power Supply Devices and Systems of Relay Protection

1

Basic Components

1.1 Semiconducting Materials and p–n Junctions

As is known, all substances, depending on their electroconductivity, are divided into three groups: conductors (usually metals) with a resistance of 10^–6–10^–3 Ωcm, dielectrics with a resistance of 10⁹–10²⁰ Ωcm, and semiconductors (many native-grown and artificial crystals) covering an enormous intermediate range of values of specific electrical resistance.

The main peculiarity of crystal substances is typical, well-ordered atomic packing into peculiar blocks—crystals. Each crystal has several flat symmetric surfaces and its internal structure is determined by the regular positional relationship of its atoms, which is called the lattice. Both in appearance and in structure, ...