The 109 is a rugged, accurate probe that measures air, soil, and water temperature for a variety of applications. It consists of a thermistor encapsulated in an epoxy-filled aluminum housing. The housing protects the thermistor, allowing you to bury the 109 in soil or submerge it in water. The 109 measures from -50° to +70°C, and it outputs a 0 to 2.2 V signal when using 2500 mV excitation.

  • Measures air, soil or water temperature
  • 109-L Temperature Probe designed to operate with the CR200 data loggers
  • Incorporates a thermistor as the active element
Output Analog
Operating Temperature Range -50° to +70°C
Sensor Description Measurement Specialties™ 10K3A1iA Thermistor
Tolerance ±0.2°C (over 0° to 70°C range)
Temperature Measurement Range -50° to +70°C
Steinhart-Hart Equation Error ≤ 0.03°C (-50° to +70°C)
Interchangeability Error ±0.1°C (over 0° to 70°C range increasing to ±0.5°C at -50°C)
Time Constant in Air 30 to 60 s (in a wind speed of 5 m s-1)
Maximum Submergence 15 m (50 ft)
Maximum Cable Length 305 m (1000 ft)
Probe Length 10.4 cm (4.1 in.)
Probe Diameter 0.76 cm (0.3 in.)
Weight 136 g (5 oz) with 3.05-m (10-ft) cable


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