Like in previous post on Automobile Engine Overheat Alert Circuit using LED, where driver gets indication through LED, but in this circuit, driver gets alert through sound and this sound comes from IC 555, which works as astable multivibrator and generates sound signal, also we can adjust temperature level for alarm using variable resistor which […]
Alarm Circuits
Simple Over-Temperature Warning Indicator Circuit
This Simple Over-Temperature Warning Indicator Circuit uses an LED to indicate excessive temperature, as it uses only a few easily available components, making the circuit simple, low cost, and easy to build. The circuit turns ON an LED when temperature rises above a set level like 45°C – 55°C and therefore, it is useful for […]
Transistor Based Water Level Alarm Circuit
Sometimes the water tank becomes full, but we forget to switch OFF the motor, as a result, the system wastes water; so, this simple Transistor Based Water Level Alarm Circuit is useful, as it gives sound alert when water reaches a level. Moreover, the circuit is cheap and easy to build as it uses very […]
Simple Two Transistor Buzzer Circuit
A buzzer is a small sound-producing device that designers use in alarms, toys, and indicators; also this Simple Two Transistor Buzzer Circuit uses only two transistors, making it simple to build and ideal for beginners. Furthermore, it works with low voltage and because of this it is safe to test, so let us understand the […]
12V Battery Low Voltage Alarm Circuit
Batteries play an important role in many electronic systems; however, their voltage drops over time, and if it falls too low, the battery may become damaged. So low voltage indication needed. Therefore, this 12 V Battery Low Voltage Alarm Circuit protects the battery by providing visual and audible alerts; also its simple, low-cost design uses […]
Low Voltage Alert Circuit for 9V Battery
Battery power plays an important role in electronic circuits, but the battery voltage can drop without warning; as a result, devices may stop working suddenly, making a low-voltage alarm necessary. This Low Voltage Alert Circuit for 9V Battery gives warning when a 9V battery goes low, as it uses LM339 comparator IC and also uses […]