Design and characterization of a 1N4148 diode-based digital thermometer with single calibration point

It has been established that the 1N4148 diode is able to operate as a temperature sensor in the range 0 0C to 160 0C. The steady state response and the dynamic response of the diode are used to support this statement. The linearity of the steady state voltage-temperature characteristics of the diode has been established beyond the range previously investigated. A digital thermometer was then designed using the 1N4148 diode as the sensor. The thermal time constant of the diode was found to be 390 ms. A comparison of the dynamic response of the diode to step temperature changes and that of a type J thermocouple was carried out and it was found that the diode had a larger thermal time constant.