Car anti-theft alarm circuit
Posted on Mar 28, 2007 12463
This paragraph Easy Car Alarm circuit with the use of fewer components, easy to produce and so on. (1) circuit automobile anti-theft alarm circuit by the time base circuit NE555, power switch VT, the switch S2, the
delay capacitor C and a resistor feet, ~ wind and other components, as shown in Figure 13-34. Sl (Sla, Slb) automotive ignition switch (open lock off). GB is a car battery, Re is the car with the ignition additional limiting resistor coil used. (2) circuit works in normal vehicle start-up operation , the switch S2 placed b-point, anti-theft circuit does not work. During the car is parked, S2 placed a point where if turned Sl, the + 12V voltage through Ri charges C IC so that pin and foot potential rise gradually while lC output of foot high level, so that VT conduction, the ignition circuit is turned on, the engine unit can start. After a few seconds delay. c charging is completed, IC's feet and to foot potential rise when 8V, IC triggers internal flip, which feet from high to low, VT cut-off, the ignition circuit is turned off, automatic engine flameout, Cars can not be driven away. Starting off with the engine sound repeatedly, the equivalent of an alarm signal.