Effects of Temperature

The normal operating temperature range for a reed contact is -40°C to +200°C, but too steep a rise or drop in temperature may crack the glass to metal seals.

When using Reed Switches, Reed Sensors and Magnet Sensors in high temperature environments, it it important to note that the effects of temperature. As the temperature rises, the Reed Blades inside lose some of their ability to carry magnetic flux and Reed Switches become less sensitive. This means that the same magnet would need to come closer for actuation. Another added effect is that the strength of the magnet also becomes weaker as temperature rises, and at it’s Curie point, loses all magnetism permanently.

Conversely, as the temperature drops, the reed switches become capable of carrying more magnetic flux and become more sensitive. The same applies to magnets also and as temperature drops, that magnets become stronger.

For high temperature applications, it is always better to select lower magnetic sensitivities (lower Operate Bands) and stronger magnets. This ensures the the slow change in environment temperature does not alter the actuation distances too much and also ensures that there is no case of non-operates.