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Alarm circuit diagrams
December 13, 2010
This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. [more]
November 8, 2010
This circuit emits a beep and/or illuminates a LED when someone touches the door-handle from outside. [more]
October 16, 2010
This circuit, enclosed in a small plastic box, can be placed into a bag or handbag. A small magnet is placed close to the reed switch and connected to the hand or the clothes of... [more]
August 4, 2010
This two-zone alarm has automatic exit, entry and siren cut-off timers. It was developed for the Beginner's Guide To Cmos Timers. So it has a particularly detailed circuit description. There's an optional One-Time-Only module. It... [more]
August 4, 2010
This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. It has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. By using the Expansion Modules, you can... [more]
August 4, 2010
When this alarm is activated its Siren will sound once - for up to 20-minutes. Then it will switch off and remain off. The basic circuit has a single zone with independently adjustable Exit and... [more]
August 4, 2010
This is a simple SCR based burglar alarm circuit. Its features include automatic Exit and Entry delays - together with a timed Bell Cut-off and Reset. The basic alarm has a single zone. This will... [more]
August 4, 2010
This transistor based alarm features automatic Exit and Entry delays - together with a timed Bell Cut-off and system Reset. Along with the Exit/Entry zone - the basic alarm board has one Instant Zone. This... [more]
August 4, 2010
The circuit features automatic Exit and Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open and normally-closed switches and will suit the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil... [more]
August 4, 2010
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 (Pressure Mats, Magnetic Reed contacts, Foil Tape, PIRs... [more]
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