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
Transistor Based Water Level Alarm Circuit
Sometimes water tank gets full which is a common problem But we forget to switch OFF the motor, because of this water gets wasted. So, this simple Transistor Based Water Level Alarm Circuit is useful. It gives sound alert when water reaches a level. Moreover, the circuit is cheap and easy to build as it […]
Simple Two Transistor Buzzer Circuit
A buzzer is a small sound making device that is used in alarms, toys, and indicators. This Simple Two Transistor Buzzer Circuit is very simple and easy to make. It uses only two transistors and therefore, it is good for beginners. Also, it works with low voltage and because of this it is safe to […]
12V Battery Low Voltage Alarm Circuit
Battery is very important in many electronic systems. However battery voltage drops with time, if voltage becomes too low then battery can get damaged. So low voltage indication is needed. Therefore, this 12V Battery Low Voltage Alarm Circuit helps to protect battery. It gives visual and sound alert and is simple and is with low […]
Low Voltage Alert Circuit for 9V Battery
Battery power is very important in electronic circuits. But many times a battery voltage becomes low without notice. As a result, devices stop working suddenly and therefore, a low voltage alarm is needed. This Low Voltage Alert Circuit for 9V Battery gives warning when a 9V battery goes low. It uses LM339 comparator IC and […]
PIR Sensor Motion Alarm Circuit Transistor and Relay
Nowadays, security is very important that why homes and shops need protection. So to safeguard this motion sensor circuits are useful. PIR Sensor Motion Alarm Circuit Transistor and Relay is simple. It uses very few components and is with low cost and is also is easy to build. The circuit works using a PIR sensor […]