The Resistance Of Water

[chuckey]

Yes, pure water contains very few loosely bonded electrons, so it does not pass current very easily. Adding salts/acid/alkali adds a lot of loosely bonded electrons so the current flows very easily. Water cooled high power transmitters use distilled water and feed it via plastic pipes to the anode of the power output device which may have as much as 10 KV DC on it. The current flow through the water is very low, so it does not short out the high voltage power supply. The converse is the electrolyte in a car battery, here the addition of the acid to the water, causes the electrolyte to be a short circuit (.001 ohm), so the battery can deliver 200 Amps when starting your car.
Frank

 

[albbg]

In water the electricity is conducted by ions; their mobility define the resistivity (or conductivity). If, for instance, you dissolve the common salt NaCl in water you will have the ions Na+ and Cl- that will be actracted by the poles of the battery (Na+ by minus and Cl- by plus). This will create a flows of charges that is a current.

 

[goldsmith]

I just know for measuring AC voltage and current we use multimeter or oscilloscope which adjusted in AC mode,is there any thing more than this?

Hi again
You can use a precise DC voltmeter and a precision rectifier to rectify the measured voltage and read it via DC volt meter . or using an MCU to read it much simpler .


Best Luck
Goldsmith

 

[andre_luis]

To synthesize an answer to the original question, we can state that for practical purposes, it is not possible to measure the resistance of the water trough of the standard techniques used in the test equipment, but in doing so we are actually measuring solely the concentration of dissolved ions compounds on pure water.



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