Bathtub water temperature intelligent heating control circuit

Bathtub water temperature intelligent heating control circuit

The picture shows the bathtub water temperature intelligent heating control circuit. The circuit includes a step-down rectifier circuit, a humidity control timing control circuit and a thyristor control circuit. When the water temperature is lower than 25 degrees Celsius, it will automatically heat for 10 seconds to keep the water temperature at around +25 degrees Celsius to 30 degrees Celsius. The step-down rectifier circuit consists of a step-down transformer T, rectifier diodes D1, D2, etc. and a voltage stabilizing circuit composed of R4 and DW (2CW57), which stabilizes the output voltage of +9V. IC1 (555) and RP1, R1, R2, C1, etc. form a temperature control monostable timing control circuit. RT is a temperature-sensitive component, using a negative temperature coefficient (NTC) glass-sealed thermistor, and the 555 works in monostable mode. In the selection of components, the temperature-sensitive resistor RT should be a negative temperature coefficient (NTC) resistor, and it is best to use a glass-encapsulated structure to prevent leakage. Potentiometer RP1 can be selected as WSW type organic solid core potentiometer. The thyristor should be a 1A bidirectional thyristor with a withstand voltage of not less than 400V, such as 3CTS1A-D type, and the transformer T should be a 5V step-down transformer with a secondary coil center tap (10V).