[sdiy] quick continuity tester?

[Scott Gravenhorst]

I would just use the visual DMM.  The reason is that
a continuity tester is really just a 2 state device,
go or no-go.  It can lie about a low resistance
connection, making you think it's zero ohms when 
it could be a couple of hundred.  Sometimes that
couple hundred ohms doesn't matter, but sometimes
it matters alot.  The DMM will tell you the whole
truth, or at least a much better version of it.
Yes, it's a slower method than an audible tool,
but far more accurate.  Just imagine a critical
ground connection that should be zero ohms and
it's not...

ElmacacoX at aol.com wrote:
>Hi all,
>
>I need a continuity buzzer to make my trouble shooting easier.  my dmm 
>doesn't have one, and I don't really want to buy a new one just yet.  
>I have a little LED roullette wheel kit I built a while ago, that runs off of 
>a 9v battery &
>it has a little 8ohm speaker, I was thinking that maybe I could make a little 
>buzzer to use for now by breaking the power connection and putting in two 
>probe wires to test the continuity by placing them over the span I wish to 
>test.  
>I imagine I don't want to be playing with 9V around the IC's, so maybe a 
>resistor based voltage divider to get it to.. what, 3V?
>
>I might be missing what a continuity tester is exactly or how it works, but 
>that's  where you guys can straighten me out I hope.
>
>so is this a bad idea?
>
>thanks
>
>Eduardo


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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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