Make cheap and easy Panic Alarm Button Circuit using IC 555, as this IC 555 work like bistable circuit with two states: alarm ON and alarm OFF. Pressing the panic button starts the timer, which stays ON until we press the reset button; the timer produces a HIGH output, turns ON the transistor, and activates […]
Alarm Circuits
Mains AC Power Supply Failure Buzzer(Alarm) Circuit
Mains AC Power Supply Failure Buzzer(Alarm) Circuit is small device; it makes sound (buzzer) when AC power goes OFF. Furthermore, it helps us to know power gone and is useful if we have important machine to know power goes at night; also it uses one switch called relay. When power is on, the relay operates […]
Motion Detector Circuit using IC 555
This easy Motion Detector Circuit uses IC 555 to find human from far, as circuit have two parts: Transmitter: IC 555 work like astable multivibrator and it make square wave signal and this signal goes out through IR sensor (infrared). Receiver: Phototransistor see IR beam and if someone moves and block the beam then phototransistor […]
Touch Alarm Circuit using IC 555
Touch metal part and buzzer makes sound and this uses IC 555 in monostable mode. IC 555 is good for learning in simple circuits and in this Touch Alarm Circuit using IC 555 when someone touches the metal plate then buzzer makes loud alarm. Circuit Working: Parts List: Components Values Quantity Resistors 1M 1/4 watt […]
Electronic Horn Circuit using IC 555
Using popular IC 555 we can make Electronic Horn Circuit for cycle, alarm or fun use, as this Electronic Horn Circuit using IC 555 and one 8Ω speaker makes loud horn sound for car or alarm. Furthermore, one 555 IC work as astable multivibrator which means it make square wave by switching high and low […]
Simple Door Open Alarm Circuit using Reed Switch
Simple Door Open Alarm Circuit using Reed Switch uses reed switch which makes alarm sound when door opens; this simple circuit help protect door from people not allowed. Also, it have reed switch, transistors, resistors, buzzer, diode and LED and here, reed switch control power to alarm. Circuit Working: Parts List: Components Values Quantity Resistors […]