Compensation of wire capacitance

[boaconstrictor]

Hi
I have the task to measure the humidity in a cabinet. This will be done by a capacitive humidity sensor. The electronic for the translation of the signal needs to be about 2m away from the sensor because the heat in the cabinet.

With the electronic of the sensor itself I don't have any problems. But the cable from the sensor to the electronic has also capacity, which needs to be compensated.

Once I heard from a cirquit which can be used for the cable capcity compensation. It seemed to work with a special cable with two shields.

Does anybody know such a circuit?

Thanks and regards boa

 

[Skogsgurra]

What you need is a "driven shield". There are several hits when you google for that. There is also an Application Note from National Semiconductor that describes how to and what not to do.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[whycliffrussell]

goole 'inductor simulator circuit'...if you cannot find anything i can send you a file with some notes later.