Light alarm schematic circuit diagram


Posted on Feb 4, 2014

This light alarm schematic circuit is designed using some common electronic parts, as you can see in the circuit diagram bellow. This light alarm schematic circuit project will sound as soon as the drawer is opened and light falls on the Darlington phototransistor. The output alarm may be redesigned to activate a relay or triac. The 14011 quad,


Light alarm schematic circuit diagram
Click here to download the full size of the above Circuit.

2 input, NAND gate is wired up to oscillate when the input to it goes high, that is the BC557 transistor turns on after light is detected by the MAL12. After the alarm has started and it is put back into dark conditions, alarm will continue to sound for about 3 - 5 seconds. This is due to the 1uF capacitor and 4M7 resistor which keep the input to the 14011 high.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Fastest Finger First project
    Acceleration sensing USB interface
    Tone-dialing-telephone
    Windshield Wiper Interval Controller
    Simple Circuit Interfaces 1-Wire Temperature Sensor To A Microcontroller
    atmel driving LEDs directly from microcontroller pins
    50MHz frequency counter V-meter & SWR/PWR indicator
    PWM motor speed controller
    220 Volts Flashing Lamps
    Amplitude Modulation
    led bicycle lights
    simplify MCU circuit design
    Boost has a frequency characteristic of automatic offset MAX630 power conversion



    Top