Technical sending unit question

Does a sending unit know if it is 6v or 12v? I have always bought new units when I bought new gauges but wonder if a factory 6v (of the correct Ohm range) can be used with a newer Stewart Warner gas gauge (if same Ohm range)

 

i've never considered fuel senders 6 or 12 volts , they are just variable resistors

 

This is a good question. Voltage = Current x Resistance. No matter the voltage, fuel sending units change proportionately to the resistance. But if you run at a higher voltage, I wonder if it changes the resistance range.

For instance:
Resistance range (20 to 300) = 6v / 0.05A

So if you change voltage to 12v:
Resistance range (40 - 600) = 12v / 0.05A

Obviously a sender draws basically zero amps, but I wonder what changing volts does to resistance range. Anyone else know this answer?

 

Had a "situation" with a temp gauge that brought up this problem. Temp reading went up when alternator output went up. Tried several senders, same deal. We had Williamson's calibrate the gauge to a sender AND 14.4 volts. Bingo, no more 220.

 

I've used original 6 volt sending units with new gauges. HRP

 

When I converted my 47 Ford tudor from 6v pos. to 12v neg. I installed Auto Meter gauges.
The original 6v pos. sender worked on 12vneg. But apparently since the sender has the wrong ohm parameters, I idle at 60# and run at 100#!
Haven't installed the Auto Meter sender yet, but at least I can see trends in my oil pressure, which is what gauges are for in the first place.
Long story longer, I'm guessing the sender doesn't care what it is, as long at it is compatible with the gauge.

 

Thanks for the input