User Manual

Pico Technology ADC-20/ADC-24 Terminal Board User Guide
DO117-5 9
2.5.3 Precision thermistor
You can use a precision thermistor in conjunction with the reference output of the
ADC-20/ADC-24 to measure temperatures accurately.
You will need to consult a table before using PicoLog to convert the voltages into
temperature readings. This can be found in Appendix 1. The figures come from the
thermistor manufacturer’s data sheet.
The diagram below shows how to connect the thermistor to the terminal board.
Temperature sensor circuit with precision thermistor
The thermistor above is an NTC (Negative Temperature Coefficient) type and should
be fitted in position R
B
. Resistor R
A
is a precision metal film type with a value of
49.9 kΩ and a tolerance of 0.1%.