Alarm Circuits

In the event of a fire, fire alarm circuits are essential for identifying and warning residents. This specific design uses an IC 555 and a thermistor to detect temperature variations that might be signs of a fire. One important kind of temperature sensitive resistor for detecting changes in temperature is the thermistor. Building the circuit […]

Building an inexpensive and simple alarm system is made possible by utilizing the IC 555 in a basic panic alarm button circuit. The IC 555 has two stable states alarm on and alarm off because it is designed as a bistable circuit. When the panic button is pressed, the timer starts and it continues to […]

A mains AC power supply failure buzzer circuit is a simple electronic device that sounds an alarm (buzzer) when the AC mains power goes out. This can be helpful for alerting you to a power outage, especially if you have critical equipment that needs to be protected or if the outage occurs at night. An […]

An alarm, such as a buzzer can be activated by touching a conductive surface in a touch alarm circuit that uses a IC 555 integrated circuit. It makes use of the multimode functionality of the IC 555 device, namely the monostable mode in this instance. Every electronics enthusiast should have at least one experience with […]

Using the well known IC 555, an electronic horn circuit may produce a range of tones for bicycle horns, alarms or even for pranks. This simple circuit, which is made up of two IC 555 and an 8Ω loud speaker, generates a louder horn sound for cars or alarm systems. As an astable multivibrator, the […]

A Door Open Alarm Circuit with a Reed Switch is a basic electrical device that sounds an alarm each time a door is opened . This simple door opening alarm circuit with a reed switch is used to secure doors against unauthorized access. Typically, this circuit consists of a transistor, resistors and a battery depending […]