> I'll stick my neck out and say that all analog multimeters
> have positive on
> the black (negative) terminal for ohms and ALMOST ALL DMMs
> have positive on
> the red (positive) lead. (It is unlikely that this will not
> be the case for
> analog meters without electronics (draw a picture) and for DMMs it is
> possible to use either polarity but makes sense to match the
> labelling.

I find amplified analog meters are pretty random in polarity.
Fortunatly they are rather rare these days.
>
> The truly competent engineer could add salt to a glass of
> water, insert the
> probes and watch the bubble formation to determine which was
> the positive
> lead :-). I must try this to see how well it works !

It might be easier to put two different coins in the salt water, measure
their cell voltage, and see if it adds or subtracts from the ohms
reading.
>
> > Even still it is hard to tell the BE junction from the BC
> > junction.  Do you have a trick I don't know?
>
> Yes :-)
> If one assumes one knows the DMM polarity (as above) one proceeds as
> follows.
>
> - Assume a base lead.
> - P (positive DMM lead) on base. N (negative DMM lead) to other two
>
{deletia}
>
>         Russell McMahon
>
I hadn't thought of doing an actual 3 port test with a wet finger.  It
ought to work.  I'll try it today.

Sherpa Doug

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