Continuity Tester based around a 555 IC

Discussion in 'The Projects Forum' started by RodneyB, May 23, 2014.

  1. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
    13
    I am trying to build a continuity tester and have found the attached circuit diagram on the internet with good reviews. I have some confusion.

    In the article they talk about a 12 Volt Pizeo Buzzer. However the circuit diagram shows an 8Ω Speaker so a little confused.

    Would any additions or alterations be suggested

    Thank you in advance
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    the 555 produces the sound at approx 1Khz in the speaker,
     
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  3. #12

    Expert

    Nov 30, 2010
    16,320
    6,818
    That chip can drive either one. Just stick in what you have.
     
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  4. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
    13
    Sorry a stupid question here but is the switch the continuity tester probes
     
  5. #12

    Expert

    Nov 30, 2010
    16,320
    6,818
    Yes.

    Apply 5 to 15 volts DC to anything, with the negative end of the power supply connected to the ground of the circuit above, and connect the positive end of the circuit to the "anything". If continuity, then buzz.
     
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