As shown in the figure, it is the circuit diagram of the rice cooker. Among them, K 1 is a magnetic steel temperature limit switch, K2 is a bimetallic insulated switch, R is a tubular electric heating element in the electric heating plate, T is a hot-melt overtemperature protector, R 1 and R2 are current-limiting resistors, L 1 is a red neon lamp indicating cooking, and L2 is a yellow neon lamp indicating heat preservation. Try to describe the working process of the rice cooker.

The principle is as follows: The strange function of the rice cooker lies in the wonderful use of two switches, K 1 and K2.

Insert the plug into the circuit, and before closing K 1, you will see the red and yellow indicator lights light up alternately. When the temperature of the inner pot starts to decrease, the bimetal switch K2 is automatically turned on, the L2 branch is short-circuited, the yellow light L2 goes out, the red light is on, and? R fever. When the temperature of the inner pot reaches 70-80 degrees Celsius, K2 is automatically disconnected, because R.

Press the magnetic steel temperature limit switch K 1 by hand. At this time, the L2 branch is short-circuited, the yellow light L2 goes out, the L 1 branch is connected in parallel with R, the red light L 1 is on, and R continues to heat up. When the temperature of the inner pot reaches 100℃, the water in the inner pot is completely vaporized. After the rice is cooked, K 1 jumps automatically, just like K2 jumps automatically, and the cycle in the previous analysis is carried out, and the temperature of the rice is kept within the range of 70-80 degrees Celsius. Once the magnetic steel temperature limit switch? When K 1 fails and the temperature of the inner pot is too high, the hot-melt overtemperature protector T will play the role of disconnecting the circuit.