For isothermal, low resistance switching of temperature measurement circuits, NEWPORT offers three styles of selector switches. The OSW style features silver plated contacts, while the OSWG line includes gold plated contacts. The SW14 1/4 DIN switches come with gold or silver-plated contacts. Each style offers 2 to 34 positions in a break-resistant Noryl case.

The isothermal design of these rotary switches minimizes temperature gradients between the input and output thermocouple wiring. This in turn minimizes errors in transmitting thermocouple signals due to the generation of a thermal emf at the wire junctions. The low resistance of the silver or gold plated contacts also enables switching of temperature sensitive resistance devices, such as RTDs and thermistors.


To allow matching of a readout device in all switch positions, the "off" position of each switch may be shorted or left as an open circuit. Each pole is fully isolated. For quick and easy wiring, the terminals located at the rear of the switch are clearly marked.

Any switch is available with a standard round knob or an optional pistol grip handle. Viewing the switch from a distance is generally easier with a pistol grip handle, as is switching its position while wearing gloves.