callibration

[Bi Hui]

Hi, how do i make my glass electrode to be able to sense pH other than 4? It only works sensing for pH 4 but not the rest. I've also looked at the link you've mentioned in the earlier post about calibration but i don't quite understand about part where u mentioned about the offset trimpot and gain trimpot.

BH

[Carlos Neves]

It works very well from pH 4 up to 10. I suggest you check your circuit out.

For the calibration, you need two buffers. Buffers pH 7 and 4 OR pH 7
and 10. My suggestion is select the couple of buffers near from your
measurements. If you sample is near from 7, it doesn't matter select
one or other couple of buffers.

The procedure is simple. Let's suppose you have the buffers pH 7 and
4. Reduce the gain to minimum and calibrates the pH using pH 7
adjusting off-set. After, calibrates using the pH 4 adjusting the
gain. Done.

The procedure is the same using pH 7 and 10.

Carlos

2012/10/21, Bi Hui <love...@live.com.sg>:

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Carlos A. Neves