DefinePK

Abstract

In the market today of temperature sensors, different methodologies of measurements were introduced such as Alcohol thermometer, Mercury thermometer, Temperature Dependent Resistor (RTD), Thermocouple that comes in different letters of calibration and temperature ranges and etc. However, there are some drawbacks using these temperature measurement technologies. And some of them must be operated with extreme caution. Like the Mercury Thermometer, usually it comes in the form of fragile glass tube packaging and has a certain temperature to operate. Operating this kind of thermometer will break instantly if exposed to temperatures out of range and releasing the highly toxic Mercury to the user or even contaminate the soil or ground water where it spilled. Thermocouples are efficient and durable in extremely high temperature measurement. But it does not produce a good reading result if the subject is vibrating or moving. Because it is dependent on the linear expansion of two different metallic elements. It may also get open circuited along the process. Temperature Dependent Resistor (RTD) is rugged and comes with different sizes where space constraint is an issue. It is linear and response but sometimes relatively expensive with respect to the range of temperature that needs to be measured. In this paper, this will give the reader an idea how to construct a precision, vibration resistant and multipoint Thermal Diode Acquisition Unit (TDAU) which uses either PNP or NPN Silicon Transistor with low ideality factor as the temperature sensor itself. The output digitized resolution will be in 32bit Analog to Digital Conversion representation.