Mindray VS-800, Service Manual

Page: 24 / 74

Principles of Operation
2-12
2.2.6
TEMP Module
General
This module provide the function of measuring the temperature.
Schematic diagram
图
2-1
TEMP schematic diagram
Principle
Normally, the sensor used for measuring temperature is a thermistor. The resistance of a given
thermistor is nonlinearly relative to the temperature. Thus, the resistance of a thermistor can be
conversed into temperature. By applying given field current to the thermistor, its resistance can be
easily obtained by measuring the voltage on the thermistor.
Temperature Detection Circuit
The resistance of the thermistor changes as the temperature change. Temperature detection circuit
converts the change of resistance into voltage difference and amplifies the signals to certain range
and then sends the signals to the sampling circuit.
Probe Recognition Circuit
Probe recognition circuit recognize the oral/axillary and rectal temperature probe of the TEMP
module.