High-Loudness Warning Sound Generator Circuit Design

　　Working principle of the circuit: This circuit is mainly composed of the sound IC KD-9561 and the switch IC TWH8778. When working, the KD-9561 outputs the alarm signal, which is processed and amplified by the TWH8778 high-current switch IC to drive the speaker to emit a loud alarm sound. IC uses KD-9561 sound IC, or KD-9562 sound IC, and connects as required to make it emit an alarm signal. IC2 uses the TWH8778 switch circuit. When the power supply voltage is 12V, the speaker BL should be selected as a speaker with 8Ω, 3W or more or a special horn speaker. The resistance value of the current limiting resistor R1 is 300Ω~510Ω, D2 uses a 3V voltage regulator tube, and D1 is a circuit protection diode, which can be 1N4001. After the circuit is installed, as long as the line is correct, it can be used normally without debugging.