Electric kettle automatic power off controller circuit diagram

　　　　The circuit working principle of this device is shown in the figure. First, use epoxy resin to dip a sheet-shaped positive temperature coefficient switching thermistor RQ on the electric kettle. Connect the two ends of RQ to the ① and ② pins of L SE , insert the kettle into the power socket CZO, and press Turn off the power switch S. At this time, due to the low temperature of the water in the kettle, the resistance of RQ is small (<50K), so the ④ pin of LSE outputs high level, the relay J immediately closes, and the normally open contact j closes. The electric kettle works when powered on. After releasing your hand, the relay J contact is self-protecting. Once the water boils (100°C), the resistance of RQ rises step by step, much greater than 50K, which is equivalent to the circuit disconnection of pins ① and ② of LSE, so pin ④ of LSE outputs low level, J is released, and its contact j Disconnect completely cuts off the power supply of the electric kettle, allowing the owner to boil water without any worries when going out. Among them, RQ should use a switching thermistor with a positive temperature coefficient, and its Curie point is 100°C.