Originally Posted by jimboot
Hi all I can light my bog standard 25watt bayonet cap 240 v lamp but I keep blowing tip41c even with heat sinks. @laurent I notice you do nt use any cooling on yours. Do they get hot? I'm using a 1k pot.
Probably the 100-110V max collector-emitter breakdown voltage limit for the TIP31C is to 'blame' for the blowing. Here is a more robust type, MJE13007
try to use such higher than 100V power switching types.