Space resolved resistance measurements of aluminum thin film resistor for potentiometer application

A disk was cut out of a sheet of etched printed circuit board (PCB) and was coated with aluminum by thermal evaporation in vacuum. The result is a device that was studied for its application as potentiometer. A rotating electrode was mounted on the disk and the resistance was recorded as the electrode was rotated. Results show that the resistance of the potentiometer varies linearly with angle and hence, distance across the coating with respect to a reference point. Results also show that as the pressure applied as the electrode was pressed onto the aluminum coating, the measured resistance decreases.