On 22/06/2010 6:19 PM, Orchid XP v8 wrote:
>>> So each time you analyse a set of samples, there is a linear
>>> conversion, but it's different each time.
>>
>> Only if the cross sectional area or length of the sample is different.
>>
>> You really need to read up on the physical properties of materials.
>
> Well, sure. I mean, it's not like the resistence of a diode varies with
> voltage.
>
> Oh, wait, actually that's exactly what it does. :-P
>
> So what makes you so certain that passing a current through a sample
> can't cause some kind of chemical reaction that affects its electrical
> characteristics, given that we don't even know what the hell this
> machine is or what it does?
>

For a start you know what units it measures and you can research how to 
measure “admittance”.
Of course passing a current through a material affects its properties. 
Even a resistor will change its resistance as you pass a current through 
it and it heats up. The trick is to use as small a current or voltage as 
will work and let the material reach its working temperature.
Electronics is not all zeroes and ones, you have to think physical 
properties as well.

As for a material having a chemical reaction:  If it were to have a 
reaction that changed its properties adversely then that is the wrong 
way to test it. Someone who understands the problem will come up with a 
solution.

-- 

Best Regards,
	Stephen

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