The fire alarm integrated circuit MC145012 integrates all the functions of the alarm. As long as the external infrared emission, receiving components and speakers are connected, it can form a fire alarm, and can also be connected with the computer to form an alarm system.
Circuit principle. LED output is driven by a 6-pin output (LED (Light-Emitting-Diode) is a semiconductor that converts electrical energy into visible light. It changes the principle of incandescent tungsten light and energy-saving lamps. According to the analysis, the characteristics of LED are very obvious, long life, high luminous efficiency, no radiation and low power consumption. The spectrum of LED is almost entirely concentrated in the visible light band, and its luminous efficiency can exceed 150lm/W (2010) ()) (D3) emits infrared light, which is received by the infrared receiving tube D2: D2 and D3 are installed in positions that are not directly opposite each other. When there is no smoke caused by fire, the D2 output is 0; if there is smoke, the infrared light is scattered by the smoke, so that D2 can receive the scattered light and trigger the alarm.
In Figure 2, adjusting the values ​​of C2 and R13 can roughly adjust the detection sensitivity; VB1 is the fine adjustment of sensitivity; SW1 is the start button; the speaker is a piezoelectric speaker; and the 7-pin is an I/O port for connecting with an external control circuit such as a computer. .
The whole machine is powered by 9V battery. When using manganese-zinc battery, C4 is 22μF. When using alkaline battery, C4 is 1μF.
Lithium Battery Cr14505,Cr14505 Lithium Battery,Primary Lithium Cells,Battery Remote Monitor System
Jiangmen Hongli Energy Co.ltd , https://www.honglienergy.com