Do these only provide a benefit if mounted to chassis or heat sink? I have never used them before and was going to use them since I have them already in my parts pin. The circuit is being built on perf board or bread board.....So I was wondering if they would provide any real benefit if they do not have a surface to transfer heat too? It is my voltage doubler/rectifier board. I was figuring that since I have them I might as well use them? If I need to I could leave them off the board and mount them to the chassis if it is going to make a big difference.