Advantages and disadvantages of pn junction temperature sensor

Advantages: high sensitivity, good linearity, fast thermal response and easy integration.

Disadvantages: the working temperature is generally -50 ~ 150℃. Compared with other temperature sensors, the temperature measurement range is more limited.

The junction voltage of crystal diode or triode PN junction changes with temperature.

For example, every time the temperature rises by 65438 0℃, the junction voltage of the silicon tube PN junction drops by -2mV. Using this characteristic, a diode (such as a glass-encapsulated switching diode 1N4 148) or a silicon triode (which can connect the collector and the base in a short circuit) can be used as a diode to make a PN junction temperature sensor. The sensor has good linearity, small volume, thermal time constant of 0.2-2 seconds and high sensitivity.

Extended data:

PN junction temperature sensor realizes the conversion of temperature and voltage. It has the advantages of thermocouple, platinum resistor and thermistor at room temperature, and overcomes some inherent defects of these traditional temperature measuring devices. It is one of the indispensable basic components in automatic control and instrumentation industry. It is widely used in the temperature range of -50 ~ 200℃. Especially in greenhouse, aquaculture, medical equipment, household appliances and other fields.

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