Quote Originally Posted by Ron View Post
THAT'S what I just couldn't remember to ask Sean about at the meet!...

I was looking at a LM107 OpAmp (with a 12V regulator, if needed) and then a 1NA117 Difference Mode Amplifier (Data Sheet Vo=V3-V2 ).
I wanted to measure the units resistance through its range if he still had it.
...Sean?
Lots of opamps can run up to 30 volts but you need to see how much current the gauge takes (check resistance). My TankZilla electronis is potted so I could not see what they used. May also need a transistor to get higher current.