Originally marketed as the Dymec DY-2801A

Operation of the DY-2800A and DY-2801A Quartz Thermometers is based on a new quartz crystal resonator which has a precisely linear frequency-to-temperature relationship. This frequency is measured digitally, using conventional electronic counter techniques.

The temperature range of the quartz thermometer is -40 to +230°C. Accuracy is equal to that previously found in high-quality platinum resistance thermometers, yet the instruments possess advantages common to digital devices: easy-to-read display directly in degrees C or F with simultaneous recorder electrical outputs. No bridge balancing is required, nor is reference to temperature conversion tables or curves.

The input has high immunity to electrical noise and cable resistance effects; sensing probes can be placed up to 1000 feet from the measuring instrument with full integrity of data; no reference junctions are required, and scanning devices are available to time-share multiple sensing probes.

The DY-2801A is equipped with two sensing probes for measuring temperature at either probe or the difference between the two. A 6-digit visual readout and recording output with a choice of pushbutton-controlled sample times provides resolution of 0.01, 0.001 or 0.0001 ºC or ºF. Signal polarity indication is provided. The 2801A includes the capability for operation as a 300 kc electronic counter.