Item anti-forgotten reminder circuit principle
There are two magnetic control switches, which are respectively installed on the left and right doors of the taxi. Each magnetic switch consists of a small water magnet and a reed tube. The small magnet is fixed on the door and the reed is laid on the door tip. The contact in the dry fence is normally off. When the passenger opens the door and gets off the vehicle, the magnet and the reed switch are separated, and the contact in the reed switch is turned on, so that the 555 pin 2 is turned to a low potential, and the 555 is set to a high potential, which provides the working power for the sink 2. IC, using 555 time base circuit. It forms a one-shot trigger circuit with R2, C1, R3, C3, etc.
The high level of the 555 output is regulated by RDw and outputs a voltage of 4.5V as the operating voltage of Ic2.
ICz uses the CM still voice integrated circuit LH560 series chip, which is a soft package structure of chip black paste, and the memory has the words "Please bring your item". The LH560 series devices have an operating voltage of 2.4-4.5V and have two trigger terminals. When used, they can be selected for high-power trigger mode. Once triggered, they will sound and be broadcasted by the vT amplifier. R5 is an oscillating resistor, which can be selected in the range of 910L-1.2M, adjust the resistance of R5, and change the tone of the voice.
Alarm release mainly uses standard equipment such as audio alarms. During wartime, communication, broadcasting, and television systems must prioritize the transmission and issuance of air defense alarm signals, and auxiliary means such as sirens, horns, and gongs can also be used. The sound alarm must be set at the designated location, and the alarm facilities must be maintained in good working condition. The release and transmission of alarms should be fast and accurate, and multiple means should be used simultaneously; Strengthen communication and liaison with superiors, subordinates, and neighbors, receive air raid intelligence information at any time, strengthen observation of air targets, and promptly report air raid intelligence; According to the situation and duration of the air raid, timely release the warning signal. With the sudden increase of air raids, the increase of attack methods, and the expansion of destruction, the importance of air defense alerts is increasingly being valued. The accuracy, timeliness, and continuous issuance ability of air defense alerts are required to be higher. The issuance methods of air defense alerts will also become more flexible and diverse with the construction and improvement of communication and network.
Early Warning System, Control Devices, Electronic Sirens, Natural Disaster Warning System, Alarm System
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