A conventional potentiometer incorporates a resistive track and mechanical wiper. The wiper is spring loaded and moves along the resistive track thereby providing for a variable resistance. Tracks can be either linear or radial and various resistive materials such as wire, conductive plastic, Cermet, etc. are used. Linear motion potentiometers incorporate a wiper attached to a shaft that moves in straight path. A rotary potentiometer has a wiper attached to a rotating shaft which moves along the radial resistive track. Again, in a conventional potentiometer, the wiper is in direct contact with the resistive material.

In a membrane potentiometer, the wiper does not make direct contact with the resistive material but instead exerts a force through the top membrane layer through to the conductive layer which in turn contacts the resistive layer. This approach yields a much higher life cycle (in the millions) all within an environmentally sealed package (IP65 or better).

Membrane potentiometers are also available in designs that totally eliminate any mechanical contact between the wiper and resistive material altogether. This is accomplished by using an external magnet and integrating a metallic layer into the membrane potentiometer. The conductive layer of the membrane potentiometer is pulled into contact with the resistive layer by the magnetic force between the magnet and metallic layer. The result is the total elimination of any actuating force on the potentiometer which yields 20+ million life cycles

Another design feature of a membrane potentiometer is its physical package. The overall thickness of a typical membrane potentiometer is < 1 mm, well under the physical limitation of a conventional potentiometer which is roughly 8 mm. A flat package also allows for a self-adhesive backing thereby accommodating a wide variety of mounting options.

Membrane potentiometers are available in standard configurations and can be customized to suit your specific applications.

Notes:
Sensofoil Magnet: A flexible iron bond is additionally implemented into the collector foil.
Sensofoil Hybrid: The upper collector foil is additionally protected by a highly flexible metal bond. Dents are avoided during longer periods of inactivity and the temperature range is enhanced as well.

For more information download our Membrane Potentiometer Brochure or contact State Electronics Parts Corp.