For simple continuity testing I use a piezo speaker with two leads/probes and a 9V battery in searies (easily obtained at Radio Shack). Loud enough to hear across the room and simple...you got a circuit, you got annoying tone; you got no circuit, you hear bupkus...
A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. Herm Albright (1876 - 1944)
