haha, u got exactly the circuit that i hv built. But i mod it with other power transistor and slightly diff design as my 1st attempt in this circuit didn't work out (light off immediately instead of slowly dim).
BTW, 2N3055 is not a good choice bcoz its metal body itself is the Collector that conducts 12V, kind of dangerous that it may short-circuit to car chassis. Don't think of insulating it as it will run hot and suppose to be fixed on to heat sink. Use TIP41C, it's a TO220 package (partially plastic) and much smaller than 2N3055...easier to fit into cabin light's casing.
