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

General Use of Precision Potentiometers

The main differences between panel controls and precision potentiometers are that precision potentiometers provide:

  • Higher accuracy
  • Better stability
  • Longer rotational life
The precision potentiometer is used in circuitry where adjustments to the voltage level or current flow:
  • Must be very accurate
  • Require frequent adjustments, and/or
  • Where a precise relationship must exist between the shaft rotation and the electrical output
In this module, the focus is on applications where more frequent and convenient adjustments are anticipated. These applications are described generally as control functions. Potentiometers used for control functions must withstand repeated man/machine interface. For most applications, rotary precision potentiometers are the most frequent type used. Adjustment of the output, or wiper position, is achieved by turning a knob or through adjustment of a "turns-counting" dial.

Precision potentiometers are devices used in applications that typically require frequent adjustment. The functions performed are:
  • Man/machine interface - manual adjustment by utilization of a knob or dial on the front panel of the equipment (normally a bushing mounted potentiometer)
  • Machine/machine interface - machine to machine adjustment by utilization of gears, couplings, or other mechanical interface (normally a servo mounted potentiometer)
Key characteristics of precision potentiometers include:
  • Frequent, sometimes constant, adjustment
  • Operating shaft extends outside as it is intended for adjustment
  • A wide price range, from under five dollars to several hundred dollars
Typical Applications

Precision potentiometers can be found in many types of electronic equipment including:
  • Electronic test equipment
  • Industrial process controls
  • Adjustable power supplies
  • Satellite dish positioning devices
  • Robotics
  • Integrated circuit test equipment
  • Computers
  • Machine to machine controls (servo systems)
Performance Parameters

There are four performance parameters that are especially important for precision potentiometers:
  • Resolution
  • Output smoothness
  • Linearity
  • Rotational Life