In winter season, water and surrounding air can go below zero degree and at that time it is useful to have a small alarm which tells us when temperature goes near freezing point. This Buzzer Alert at 0°C Indicator Circuit uses thermistor sensor, one op-amp IC and a piezo buzzer to make sound alarm when […]
Security and Protection
Slow Voltage Rise Power Supply Circuit
Sometimes when our circuit power is ON a big current comes suddenly and this sudden current can damage parts like IC, capacitor and transistor; so to stop this we make Slow Voltage Rise Power Supply Circuit. This circuit gives voltage slowly but not full at once, so circuit become safe and work is quite reliable. […]
LDR Based Aircraft Warning Signal Light Circuit
Tall buildings, towers and other high structures require warning lights to ensure aircraft safety and a red 230V LED bulb typically serves as the warning lamp. This LDR Based Aircraft Warning Signal Light Circuit automatically switches ON the bulb in night and switch OFF in day, also it uses LDR sensor, relay and small power […]
Refrigerator Door Open Alarm Circuit with IC 555
Sometimes, people forget to close the fridge door and this causes loss of cooling and waste of electricity; so to solve this problem we can use a simple Refrigerator Door Open Alarm Circuit with IC 555 When the door stays open, the buzzer gives a sound, so it reminds the user to close the doo; […]
Magnetic Proximity Switch Sensor Circuit
The Magnetic Proximity Switch Sensor Circuit detects magnetic fields to operate in factories, security systems and automation applications; also a magnetic reed switch serves as its main sensing component. ICs like 555 timer and CD 4013 flip-flop turn relay ON/OFF when magnet is close by and then relay control other device ON/OFF. Moreover, circuit need […]
Simple Dark Sensor Circuit for Security using IC 555 timer
Simple Dark Sensor Circuit for Security using IC 555 timer is useful project for security, it senses low light and turns ON the buzzer or light. Also, the circuit uses an LDR for light sensing and works well in night lights and alert systems. Furthermore, it includes a 555 IC, an LDR, resistors, a capacitor […]