pH meter Use

[Rakestraw]

I have a question reguarding the use of a desktop pH meter, The meter I am using comes with a BNC cap that shorts out the input to the pH meter, but I have to remove the cap to use a pH electrode to make measurements, what is the cap used for? and when would I use it?

 

[IRstuff]

The shorting cap is probably used to protect the input to the meter from damage, either through handling or ESD.

Considering that DI water is at 18 megohm-cm, one can imagine that the pH meter input is very high impedance and susceptible to static damage.

TTFN

 

[kenvlach]

The cap simply keeps the terminal clean when you don't have a probe attached. It doesn't actually short anything out (the + and - aren't connected).

Have used all sorts of benchtop and portable pH meters in academic and industrial settings, and never heard of ESD being a problem. Not mentioned in Corning or Fischer manuals, either. High humidities, corrosive atmospheres and sloppy users were sometimes a problem.