Ravi <echip.india <at> gmail.com> writes:

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> Hi Guys,
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> I have a 555 based oscillator, AC couple and the probes are in salt=20
> water of a given concentration.
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> The probes are in water for about 1 hour from 8 PM to 9 PM and the=20
> reading is 6500 Hz. I switch off the unit.
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> The next day at 9 AM in the morning I see that the value has changed to=20
> 7000 Hz.
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> What could be causing the drift?
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> Cheers
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> Ravi
>=20

The conductivity of saline solution has a high temperature dependance.

http://www.fondriest.com/environmental-measurements/parameters/water-qualit=
y/conductivity-salinity-tds/#cond16

The above suggests 2% to 4% increase in conductivity for a 1 Celsius
increase in temperature.

Regards

Mike



--=20
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