Audio Lm 3909 IC-conduction tester Circuit Diagram

This tiny conductivity tester works with LM 3909. The tester makes a beeping sound if the resistance between the test probes between 0 and 100 O lies. Due to the volume of the beep, the resistance between the test probes can be determined.

Audio Lm 3909 IC-conduction tester Circuit Diagram

Parts List

     R1 = 1 k
     C1 = 10 uF
     C2 = 100 nF
     LS = Loudspeaker 12 to 16 Ω
     IC1 = LM 3909