The forward characteristics of thyristors

A theory on the forward V-I characteristics of P⁺-P-N-P-N⁺thyristors is proposed. Taking the minority carrier lifetime in the base region into account, the effects of the device structures on the forward characteristics are discussed on the following three cases: 1) low-level operation, 2) middle-level operation, and 3) high-level operation. At middle-level operation, the term that is independent of current and, at high-level operation, the √I dependency, appears in the forward characteristics of the thyristors. The general theory is illustrated by reference to experimental results on silicon-controlled rectifiers.