This article summarizes the hardware organization and working principles of the thyristor zeropassage trigger capacity control circuit which have a singlechip as its main body.

The paper surveyed the thyristor models which are usually applied to computer simulation of thyristor circuits and discussed in detail the principles, features, advantages and shortages of the models.

To introduce the composition and working Principle of a thyristor rectifier unit of large power for DC EAF.