continuity tester devresi

Parts List: R1 = 1K D1,D2 = 1N4148 R2 = 2K2 Z1 = 8V2, 1/4 watt R3,R4 = 22K T1 = 2N3905 (PNP) R5 = 2K7 T2,3,4,5 = 2N3904 (NPN) R6,R7 = 56K 9volt Alkaline battery R8 = *See text suitable loudspeaker C1,C2 =...