What is the principle of air defense alarm? How so loud ah?
General air defense alarm equipment are set in the roof of the building of the city, by the armed departments or streets, enterprises and institutions to manage the security sector. The sound is "mechanical" waves, and through the air spread to people's ears. So as long as the air can "shake" the method, can sound.
3, the power supply system: power supply system and sub-power supply and self-powered two.
2, control equipment: control equipment is divided into two kinds of wired control and wireless control.
1, the alarm: the alarm is divided into two types of motor and electro-acoustic. The motor type has a motor as the main device of the siren, turning the mechanical energy into sound. The electro-acoustic type is composed of the main function and the speaker.
