CMOS Single Zone Alarm Zone Alarms | Single Zone Alarm     Site written by Ian King

Homepage Site Contents Map Back Alarms   Single Zone   Multiple Zone Fire Alarm   Simplex   Edwards   Notifier   National Alarm Code   Inspection   Equipment   Installers   Manufacturers Burglar and Fire Reference Page Index A to Z Contact us Single Zone - Single zone fire alarm circuit diagram and description. This contrasts with a multiple zone alarm where there are two or more zones. A single zone alarm has only one zone. Burglar and Fire - Info on fire and burglar alarm systems, links to burglar and Fire security alarm systems. CMOS Single Zone Alarm. Circuit diagram and technical description of a burglar alarm, specifically a CMOS Single Zone Alarm. CMOS single zone alarm. Please refer to diagram below Description: This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally open and normally closed switches and will accommodate the usual input devices such as Foil Tape, Pressure Mats, Magnetic Reed Contacts, Passive Infrared Detectors and Inertia (Shock) Sensors. Notes: The green Led should be lighting before you set the alarm. When you open SW1 The red Led will light and the Exit delay will begin. You have about 30 to 40 seconds to leave the building. As you do so the buzzer will sound. It should stop sounding when you close the door behind you; indicating that the trigger circuit has been successfully restored within the time allowed. On returning, when you open the door the buzzer will sound again. You then have about 30 to 40 seconds to move SW1 to the "off" position. If you fail to do so, the siren will sound. After about 15 to 20 minutes, when the relay drops out, the alarm will attempt a Reset by using Q3 to switch itself "off" briefly. If the trigger circuit has been restored the alarm will reset. If not, the attempt will fail and the alarm will reactivate. It will go on trying to reset itself every 15 to 20 minutes until the trigger circuits are restored; or the alarm is switched off. The Exit delay, Entry delay and Bell Cut-off times may be changed by altering the values of R12, R8 & R11 respectively. The sensitivity of the Inertia Sensors is adjusted by R4. Set to minimum value, a light tap will activate the alarm. Set to maximum value, a heavy blow is required. If you are not using Inertia Sensors then replace R4 with a 220k fixed resistor. If you are not using normally open switches then leave out R1, C1 & Q1 and fit a link between the green Led and C2.

CMOS single zone alarm burglar alarm circuit - (Click to enlarge) Site structure created by Ian King Site written by John Middlemas, Ian King, & Pascal Walls