Alarm control
No description available.
Single-Ic Alarm
With a single integrated circuit (IC), it is possible to construct a straightforward and dependable auto burglar alarm or a similar alarm system. Refer to (a) for the timing information related to the alarm circuit in (b). When leaving the...
Alarm Sounder For Flex Switch Circuit
This is a cross-sectional diagram of a flex switch. They can be used as pushbuttons or even position sensors. This schematic diagram shows an oscillator, which is used as an alarm sounder, triggered by a flex switch.
The flex switch is...
Electronic Door Buzzer
When the switch SI is pressed, a positive voltage is applied to capacitor C2 and the non-inverting terminal of operational amplifier U1. The circuit oscillates at a low frequency initially. As capacitor C2 charges through resistor R3, there is a...
Automatic plant waterer
The unit consists of a sensor, timer, and electric water pump. The sensor is embedded in the soil, and when dry, the electronics operate the water pump for a preset time. The circuit is composed of a level-sensitive Schmitt trigger,...
Mini Alarms
This is a selection of small self-contained alarm circuits. They have a very low standby current; and are suitable for battery operation.
The described alarm circuits are compact and designed for low power consumption, making them ideal for battery-powered applications. These...
Alarm Power Supply
This power supply is suitable for a modular burglar alarm but can also serve other applications. It is designed to provide a 12-volt output with a current capacity of up to 1 amp. In case of mains failure, the backup...
No Doze Alarm Circuit
This circuit emits a loud tone if the input switch (S2) is not retriggered at designated intervals. If the user falls asleep and fails to re-trigger the circuit, it will continue to sound until S2 is pressed.
The circuit operates on...
Alarm interface circuit
Alarm interface circuitry featuring a two-color light-emitting diode (LED) display. When LAi is at a high level and LBi is low, the green LED lights up; conversely, if LAi is low and LBi is high, the red LED lights up....
Two HiJack Alarms
The first circuit was designed for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when...