Simple continuity tester


Posted on Feb 10, 2013

The pitch of the tone is dependent upon the resistance under test. The tester will respond to resistance of hundreds of kilohms, yet it is possible to distinguish differences of just a few tens of ohms in low-resistance circuits. Ql and Q2 form a multivibrator, the frequency of which is influenced by the resistance between the test points.


Simple continuity tester
Click here to download the full size of the above Circuit.

The output stage Q3 and Q4 will drive a small loudspeaker or a telephone earpiece.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    STRESS METER
    Three-phase switch
    B-Field Measurer
    how to build water level indicator
    12v automotive electrical voltage
    car battery charger schematics
    Magnetic core memory reborn
    Barricade warning light flashing circuit



    Top