Method for judging active and passive thermocouples

1. The basic principle of thermocouples
A thermocouple is a sensor that uses the thermoelectric effect to measure temperature. A thermocouple is formed by connecting wires of two different metal materials. When the positions of the two contacts are at different temperatures, a temperature difference is formed, which generates a thermoelectric potential. By measuring the magnitude of this thermoelectric potential, the temperature can be determined.
2. Differences between active thermocouples and passive thermocouples
The difference between active thermocouples and passive thermocouples lies in whether external power supply is required.
3. Methods for determining the active and passive nature of thermocouples
The main method to determine the active and passive nature of thermocouples is to observe the connection method of the thermocouple joints and leads.
The connector of an active thermocouple is usually a socket with both leads present, and a plug-in lead can connect the thermocouple to the power supply. Active thermocouples can actively generate thermal potential without the need for external power supply, so they only need to be inserted into the measuring instrument during use.
The joint of a passive thermocouple is usually a plug-in lead without a lead socket. Passive thermocouples require external power supply, so their leads need to be inserted into the external power supply before being connected to the measuring instrument for normal operation.
By observing the connection method of the thermocouple joints and leads, we can determine whether the thermocouple is active or passive. Active thermocouples do not require external power supply, while passive thermocouples need to be connected to an external power supply to function properly. In practical applications, choose the appropriate type of thermocouple as needed.