Abstract: Besides dealing further with the advantages of the use of MOSFET as a rapid switch and some principal types of main circuit of arc welding inverters,this paper discusses how to solve the problem of the increase of output power of the new type of arc welding inverters developed by the author.This is done by means of experiments,the derivation of the corresponding formulae and both statical and dynamic analyses of the current oscillogram for the parallel transistor-group.