Product Application
Modern refrigerators are evolving and offering more functions. Quick-chill settings help reduce temperature fluctuation. Dual cooling system often includes two separate cooling circuits to allow the refrigerator and freezer to be controlled separately. Some smart refrigerators even offer multiple independent drawers so that consumers can adjust refrigeration conditions to the precise temperature based on the type of food stored inside. NTC temperature sensors, also known as NTC thermistors, are used to help regulate the refrigeration temperature in each section because they are simple, effective, and accurate temperature sensing elements. THINKING provides a variety of NTC temperature sensors for refrigerators.
The latest refrigerators come with advanced features such as wireless connectivity and touch screens. The increased number of electronics makes associated circuit protection more complex and critical. In addition to temperature sensors mentioned above, THINKING offers a broad line of circuit protection components to protect the complex and sensitive circuits and recommends the following protection technologies for use in the applications.
THINKING’s plastic type NTC temperature sensors are perfect for applications in various parts of the fridge including the evaporator, ice bin, motor, refrigerator and freezer applications. For the sensor, its sensing top filled with insulation glue makes it moisture resistant, impermeable, and reliable. Putting reliability as the top priority, the NTC temperature sensor is tested for storage in water (5000 h at +30 °C) and for operation in ice (3000 h at -20 °C). The test results shown below indicate that the temperature sensor experienced minimal temperature swings in the humid and freezing environment, and the temperature remains stable for thousands of hours. For preventing the evaporator from icing, an NTC temperature sensor potted in a brass housing with stainless steel clip can be easily snapped onto the evaporator tubing.
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- THINKING’s Metal Oxide Varistor (MOV) protects the power input from overvoltage, and the NTC or PTC inrush current limiter effectively prevents it from inrush current.
Components on the control board such as MOSFET and ICs are vulnerable, and they are suggested to be guarded by MOV. Some designers may choose TVS diodes to protect the circuits from threat of voltage transients.
- Motors often risk from the damage of overload, stall, and overheating. Ceramic PTC thermistor is suggested to be installed to prevent the motors from the damage of overcurrent. An NTC temperature sensor is also recommended for monitoring the temperature to prevent the motor from overheat.
- Like the portable consumer devices, refrigerators equipped with touch screens and wireless connection systems are exposed to the threat from electrostatic discharge (ESD). A multilayer varistor or an ESD TVS diode is recommended to attenuate the energy.
