Abstract: A conductive polymer device includes an active element comprising a conductive polymeric layer laminated between a pair of electrodes to which terminal leads are attached. The active element is enclosed in an insulative package. Each of the electrodes may be formed integrally with its associated terminal lead in a single lead frame, with a layer of conductive polymeric material laminated between two such lead frames. Alternatively, a conductive polymeric layer may be laminated between two electrodes, with a terminal lead then being soldered to each electrode. The insulative package for the active element may be either an over-molded housing encasing the active element, or a pre-molded housing having a cavity into which the active element is installed, and which is then hermetically sealed with a suitable sealant material.

Abstract: A ratcheting mechanism for a multiturn variable resistance device, of the worm screw-actuated type, has mutually engageable stopping members on the rotor and in the housing, limiting rotor travel beyond first and second limits. The stopping member in the housing has an inclined surface on one side which pivotally lifts the rotor against the force of the electrical contact spring (carried on one side of the rotor in contact with a resistive element), when the rotor reaches the first limit of travel. The pivoting action compresses the contact spring while allowing the spur gears on the rotor momentarily to disengage from the worm gear. This disengagement releases the spring, which then urges the rotor back into a gear-engaging position. The rotor is provided with at least one axially-shortened spur gear tooth positioned so as to be engageable with the worm gear when the rotor is at the second limit of travel.