Refrigerator closing prompt circuit

Key words: Refrigerator, close This circuit can automatically issue a "Please close" prompt voice, remind the owner to close the refrigerator door in time. The circuit is shown in the figure. The left side of the dashed line is the refrigerator lighting control circuit, where S1 is a refrigerator lighting gate control switch; the right half is a refrigerator closing prompt circuit. When the refrigerator door is opened, the SL is automatically closed, the lighting light h is lit, the AC power supply of the H-terminal converted by CL, VDL ~ VD5, and C2, the output of about 3.9V DC is output to the prompt circuit. This DC power source is charged to C3 through R3. Since the voltage across the capacitor cannot be mutated, the positive end of C3 is still low at the time of opening the door, and the VD6, VTL is closed. The VT2 is therefore closed, the ICL language integrated circuit HFC 5203 does not work, the speaker BL does not sound. When the voltage of the C3 charges to about L.3V, VD6 and VTL are turned on by the cut-off transfer, and the triode VT2 is also turned on. The ICL is powered by power, and BL issues "Please close" voice sound. R5, C5 value determines the high low of the voice tone, using the illustration parameter "Please close the door". If you increase C5 to 560pf, you become a male voice "please close".

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