Build Intelligent Wire Loop Alarm Circuit With IC

Integrated circuit anti-theft alarm system, wire or other lack of a simple circuit. When the lack of wires or cords lacking. MOSFET, it is working or has input voltage at pin G and thus it has a high current flows through the pin D-S that Micro piezo siren was so loud.

Part List

R1  100K 1/2W 1% Resistor
R2, 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 type of hookup wire, with a maximum resistance of about 90K. Using very thin wire (40AWG, for example) will make a very sensitive trip wire, but will shorten the distance it can be strung due to the high resistance.

 The siren can be replaced with a relay to drive external load