====== Rectilinear Potentiometer ======

The A-4 Trainer came equipped with 3 similar assemblies for the 3 main flight controls, Aileron, Elevator, and Rudder. 

To detect the position, each has a "Rectilinear Potentiometer." This is a linear sliding potentiometer with 6 electrical connections instead of the usual 3. 

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Disassembled to make sure wiper was connecting well. Looks good inside, lightly lubricated. Measured resistance between connection pins. With the exception of the "S" connection, which connects to a metal strip which is ridden by the wiper, the connections just connect to a continuous resistive strip. I don't need it for this application, but the rudder for example, could use the CT as the center.

^Terminal^From - (Minus) Ohms^
^-|0|
^1|1.6K|
^CT (center tap?)|6.4K|
^2|10.4K|
^+|12.1K|

The "S" terminal must be "Slider" which is connected to the Wiper.

The normal connections to use with Arduino DAC would be:
^-|Ground|
^S|DAC Input|
^+|Vcc or 5V|

10/19/2019