ok, i processed some with this project. now, the problem is thermal runaway of the transistor, if i got it right: more current->more heat->more current->more heat.....until transistor is overheated, or PSU's fuse will blow (unlikely?) i thinked about this problem, and i thought about more cooling (bigger heatsink, fan, or even thermal shut-off) but, i thought i should ask here too, so is there any workaround in this problem? i could add extra transitor in paraller with exicting one to inrease amperage handling, but this involves adding some cind of small resistance resistors in transitors emitters to balance current between transitors. but, what do you think for solution?