Ceiling fan circuit diagram that can automatically start according to room temperature

As an electronic engineer, whether you are just getting started or have extensive experience, you need to have a certain knowledge of circuit design. Of course, this does not refer to theoretical knowledge of circuits, but the ability to do it yourself. In this article, the editor will introduce to you the temperature control circuit diagram of a Breeze ceiling fan. This design can switch between starting and shutting down according to the room temperature.

Figure 1 shows the breeze ceiling fan temperature control circuit. It consists of a temperature measurement control circuit and a step-down rectifier power supply circuit. The power circuit provides a DC voltage of VDD=+5V for the control circuit. The core of the temperature measurement control circuit is a bistable trigger composed of IC (555) and R5, R7, W1, R6, etc., and R6 and R7 use NTC thermistors as temperature measurement components.

When the ambient temperature increases, the corresponding resistance values ​​of R6 and R7 become smaller, causing the IC to be set because the potential of pin 2 drops to less than 1/3VDD, and pin 3 outputs a high level. As a result, the thyristor AC zero-voltage switch composed of D2 ~ D5, SCR, BG1, BG2, etc. is turned on, and the fan D runs because the power is turned on; when the ambient temperature drops, the corresponding resistance values ​​of R7 and R6 become larger. The 555 is reset because the potential of pin ② rises to greater than 1/3VDD, and pin ③ outputs a low level, which causes the thyristor AC zero-voltage switch to cut off, and the electric fan D stops due to the power disconnection.

During debugging, the test temperature can be adjusted. When the ambient temperature is higher than the temperature set by the designer, the fan will automatically turn on. When the ambient temperature is lower than the temperature given by the designer, the fan will stop working. Potentiometer W1 is a stabilizing potentiometer, and the corresponding temperature can be marked with a dial. If you have time, you can try to build such an interesting ceiling fan circuit diagram.