testing my homebrew psu

[m3vuv]

hi all,ive just been playing with the current limiting ie cc mode on my cobbled psu,it acts wierd,ive been testing with a 10watt 12v bulb,am i right in thinking the resistance will be low when the fillaments cold and high it seems too take more winds on the current pot to light it then i can wind the pot down quite a way to go into cc mode,its hard to explaine,is this normal?