Temperature probe for DMM

TEMPERATURE PROBE FOR DMM This article deals with a plug-in temperature-to-voltage converter for use with a digital mu/timeter (DMI14) The design includes a battery test facility and a home-made probe for ease of measurement. The Type LM35 from National Semi- conductor is stated to have the fol- lowing features:* ‚ñ† Calibrated direct in degrees Cel- cius (Centigrade) (¬?C). ‚ñ† Linear +10.0 mV/¬?C scale factor. ‚ñ† 0.5 ¬?C accuracy at +25 ¬?C (LM35C). ‚ñ† Rated for full -55 to +150 ¬?C range. ‚ñ† Suitable for remote applications. ‚ñ† Operates from 4 to 30 volts. ‚ñ† Less than 60 IAA current drain. ‚ñ† Low self-heating, 0.8 ¬?C in still air. ‚ñ† Non-linearity only ¬±0.25 ¬?C typical. ‚ñ† Low-impedance output, 0.1 Q for 1 mA load. the proposed temperature probe. Diodes D3 and D4 have been in- cluded to obtain a circuit ground potential which is some 1.2 V lower than that of the temperature sensor. Resistor R5 ensures that the sensor output voltage can be negative with respect to ...