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Introduction • On Precision Pots • General Product Definitions • Construction Details • Multiturn Precision Pots • Resistive Elements • Terminals • Shaft-Rotor Assembly • Mechanical Rotation • Mounting Methods • 3540 Family • 3590 Family • Knobpot 3600 Family • Single-Turn Precision Pots • 6537/6637 Family • 6539/6639 Family • 3680 Pushbutton Family • Special Precision Pots • Shafts • Mounting Styles • Bearings • Torque • Linearity • Wiper Load • Low Current Applications • High Rotational Speed • Angles • Additional Taps • Sealed Units • Multicup Assemblies • Envelopes •
Environmental • Competition •
Useful Terms
Resistive Elements
Multiturn precision potentiometers use two kinds of elements:
- Wirewound
- Hybritron® (wirewound element with a conductive plastic coating)
In both cases, the resistance wire is wound on an insulated copper mandrel. The mandrel is then formed into a helix and cut to the proper diameter and number of turns.
In hybrid elements, a conductive plastic resistance material is then deposited on the inside surface of the helix of a wirewound element, filling the space between the wires. (The result is a smoother output as the wiper moves across the element.) A typical hybrid is the Hybritron® element.
The hybrid element exhibits the temperature coefficient and resistance stability of a wirewound element, while displaying the long operational life and essentially infinite resolution typical of conductive plastic devices.
The technology used in manufacturing wirewound elements is one of the many core competencies that Bourns has developed.
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