What is the difference between three-wire and two-wire temperature sensors?

Temperature sensor is a sensor for measuring temperature, which is widely used in industry, scientific research, medical treatment and other fields. According to the different wiring methods, temperature sensors can be divided into three-wire and two-wire systems. The following article will introduce the differences between these two temperature sensors in detail.

1. Differences in wiring methods

A three-wire temperature sensor usually has three pins, namely the positive power supply, signal output, and negative power supply. A two-wire temperature sensor only has two pins, namely the power supply and signal output. This wiring difference is the most obvious difference between the two sensors.

1. Differences in measurement principles

Three-wire temperature sensors usually use thermocouples or thermal resistors as measuring elements, and measure temperature by measuring the resistance or voltage change of the measuring element. Two-wire temperature sensors usually use semiconductor materials as measuring elements, and measure temperature by measuring the resistance change of the measuring element.

1. The difference between accuracy and stability

Since the three-wire temperature sensor uses thermocouples or thermal resistors as measuring elements, its measurement accuracy and stability are relatively high. However, the two-wire temperature sensor uses semiconductor materials as measuring elements, and its measurement accuracy and stability are relatively low.

1. The difference in anti-interference ability

The three-wire temperature sensor can effectively reduce interference in the line and improve the accuracy of measurement because it uses a three-wire wiring method. However, the two-wire temperature sensor has only two pins, so its anti-interference ability is relatively weak.

1. Differences in application scenarios

Since three-wire temperature sensors have high measurement accuracy and stability, they are usually used in scenarios with high requirements for temperature measurement accuracy, such as scientific research, medical treatment, etc. However, due to their low cost, two-wire temperature sensors are usually used in scenarios with low requirements for temperature measurement accuracy, such as household appliances, industrial equipment, etc.

1. The difference between installation and maintenance

The three-wire temperature sensor has three pins, so its installation and maintenance are relatively complicated. However, the two-wire temperature sensor has only two pins, so its installation and maintenance are relatively simple.

1. The difference in cost

Since the three-wire temperature sensor uses thermocouples or thermal resistors as measuring elements, its cost is relatively high. However, the two-wire temperature sensor uses semiconductor materials as measuring elements, and its cost is relatively low.

1. The difference in temperature range

Three-wire temperature sensors can usually measure a wider temperature range, such as -200℃~1300℃. However, two-wire temperature sensors can usually only measure a narrower temperature range, such as -40℃~125℃.

1. The difference in response time

Since the three-wire temperature sensor uses thermocouples or thermal resistors as measuring elements, its response time is relatively long. However, the two-wire temperature sensor uses semiconductor materials as measuring elements, and its response time is relatively short.

1. Differences in power requirements

Three-wire temperature sensors usually require a higher power supply voltage, such as 24V or 48V, while two-wire temperature sensors usually only require a lower power supply voltage, such as 5V or 10V.

1. The difference between signal transmission methods

Three-wire temperature sensors usually use analog signal output and need to be converted by analog signal processing circuits, while two-wire temperature sensors usually use digital signal output and can communicate directly with digital devices.

1. The difference in anti-electromagnetic interference ability

The three-wire temperature sensor has a relatively strong anti-electromagnetic interference capability due to its three-wire wiring method, while the two-wire temperature sensor has a relatively weak anti-electromagnetic interference capability due to its only two pins.

1. The difference in environmental adaptability

Since the three-wire temperature sensor uses thermocouples or thermal resistors as measuring elements, its environmental adaptability is relatively strong and can adapt to harsh environments such as high temperature, high pressure, and corrosion. However, since the two-wire temperature sensor uses semiconductor materials as measuring elements, its environmental adaptability is relatively weak.

1. The difference in lifespan

The three-wire temperature sensor uses thermocouples or thermal resistors as measuring elements, so its life is relatively long. However, the two-wire temperature sensor uses semiconductor materials as measuring elements, so its life is relatively short.