The aim of this paper is to investigate the behaviour of the break-over voltages of thyristor structures, based on wide bandgap materials, under different conditions. Influence of the narrow and wide base width, electron/hole lifetime, shunt and collector resistance, donor/acceptor concentration, temperature, and charge carrier recombination time on the break-over voltage has been investigated and analysed. On the basis of this information it is possible to make suggestions to the designers of the device to avoid expensive practical experiments.