Why can a transistor be used as a temperature sensor? 2

So, why can a transistor be used as a temperature sensor? This is mainly because there is a certain relationship between the base emitter voltage and temperature of a transistor. When the transistor operates in the saturation or active region (i.e., the base emitter voltage is greater than 0.7V), the base emitter voltage decreases with increasing temperature, and this characteristic is widely used in temperature sensors.

Specifically, the variation of the base emitter voltage of a transistor with temperature can be expressed as Δ V_BE=-2mV/° C. This means that every time the temperature rises by 1 ° C, the base emitter voltage will decrease by 2mV. Therefore, by measuring the base emitter voltage, the temperature can be accurately calculated. That's why transistor can be used as temperature sensors.

In summary, transistor can be used as temperature sensors mainly because their conductivity and amplification are temperature dependent. By measuring changes in these parameters, we can obtain measurements of temperature. Moreover, due to its small size, fast response speed, high accuracy, and low cost, the transistor temperature sensor is widely used in practical applications. However, as a basic semiconductor device, the transistor can not only be used for amplifying and switching circuits, but also as a temperature sensor by utilizing its characteristics, providing convenience for our daily life and scientific research.