Friday, April 12, 2013
Build Intelligent Wire Loop Alarm Circuit With IC
Integrated circuit anti-theft alarm system, wire or different lack of a easy circuit. When the shortage of wires or cords lacking. MOSFET, it's working or has input voltage at pin G and for this reason it has a high current floats in the route of the pin D-S that Micro piezo siren was once so loud.
Part List
R1 100K 1/2W 1% ResistorR2, R4 10K 1/2W 1% Resistor
R3 1 Meg 1/2W 1% Resistor
C1, C3 0.1uF Ceramic Disc Capacitor
C2 0.01uF Ceramic Disc Capacitor
IC1 4001UBE Quad 2-i/p NOR Gate
Q1 MPSA14 Low Power NPN Transistor
SIREN Micro piezo siren 12V DC 150mA, 110dB @ 1M
LOOP See “Notes”
The loop can be any kind of hookup wire, with a most resistance of about 90K. Using very skinny wire (40AWG, for example) will make an awfully sensitive travel wire, but will shorten the distance it will also be strung due to the high resistance.
The siren can be changed with a relay to power external load
