Rice Cooker Temperature Sensing Using Reed Switches

A Rice Cooker is a kitchen appliance used to boil rice and continue to keep the rice warm and hydrated. As more heat is required to boil the rice than to keep it warm, an inbuilt thermostat needs to be used for heater control. When the cooking timer starts and the rice is then boiled, the thermostat checks if the temperature is going up and then switches the heaters to a low power mode.

The problem with thermostats in a Rice Cooker is that they are constructed using two dissimilar metals that expand differentially and break contact at the required point. The disadvantage is that depending on the current the heater is drawing, the set point also varies. This is where Thermal Reed Switches are accurate for heater control applications. Another advantage is the Thermal Reed Switches are capable of switching heater loads via a small Reed Relay and no extra amplification circuits are required.

After the rice cooker has switched to the warm mode, a Thermal Reed Switch can maintain the rice in a rice cooker between 65°C and 68°C by directly signalling the heaters. Some rice cookers also have reed sensors to detect whether the lid has been placed properly so that heater is not turned on continuously. A simple Reed Switch and magnet can also be used to detect if the rice cooker bowl has been placed in the cooker instead of the conventional mechanical switches.

Application Classification

Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.

Temperature Sensing Type

Normally, Reed Switches are used in collaboration with magnets in all the other types of applications. A Thermal Reed Switch is not Continue reading -> Sep 3, 2024

Recommended Products

The Reed Switches and Sensors used in such heater control applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.

Thermal Reed Sensor TRS-P for AC Loads

Drawing of TRS-P Thermal Reed Sensor starFeaturesTemperature range of 25°C to 130°C. Less than 3°C tolerance. Normally Closed Continue reading -> Sep 3, 2024

Thermal Reed Sensor TRS-W

TRS-W Thermal Reed Sensor Drawing starFeaturesTemperature range of 25°C to 130°C. Less than 3°C tolerance. Normally Closed Continue reading -> Sep 3, 2024

Line Voltage switching Reed Switch, LV-1925

Full Length LeadsCropped LeadsSMD Formed LeadsVertical MountingHorizontal Mounting starFeaturesContact Rating Configurable. Ruthenium Continue reading -> Sep 3, 2024