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Sensors and Detectors

Simple Dark Sensor Circuit for Security using IC 555 timer

Last updated on 22 June 2026 by Admin-Lavi Leave a Comment

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 […]

Filed Under: 555 Timer Projects, Automation Circuits, Mini Projects, Security and Protection, Sensors and Detectors

Dual LED Temperature Indicator Circuit

Last updated on 22 June 2026 by Admin-Lavi Leave a Comment

Dual LED Temperature Indicator Circuit light one LED when hot and other when cold and it uses IC LM35 temperature sensor, CA3130 op-amp and two BC547 transistors. IC 7805 change 9V to steady 5V and if there is 5V already then we can connect directly, then IC LM35 gives 10mV more for every 1°C rise. […]

Filed Under: DIY Projects, Heater and Temperature Controllers, Indicator Circuits, LED and Lamps, Sensors and Detectors

Temperature Based DC Fan Controller Circuit using Transistors

Last updated on 21 June 2026 by Admin-Lavi Leave a Comment

Temperature Based DC Fan Controller Circuit using Transistors turns ON when hot, stops overheating and saves energy, then thermistor checks temperature and runs fan as needed. Also, the circuit works on 12V battery or 12V power supply. Circuit Working: Parts List: Components Values Quantity Resistors (All resistors are 1/4 watt unless specified) 1.5k 1 1k […]

Filed Under: Heater and Temperature Controllers, Sensors and Detectors, Transistor Circuits

Temperature Controlled Fan Circuit for Audio Amplifiers

Last updated on 19 June 2026 by Admin-Lavi Leave a Comment

Amplifiers make heat when working, also too much of heat make it work bad and can die soon; therefore, this Temperature Controlled Fan Circuit for Audio Amplifiers keep amplifier cool. Fan starts only when amplifier is hot and if volume is low and less heat then fan stays OFF and saves power. Also, the circuit […]

Filed Under: Amplifier Circuits, Audio Circuits, DIY Projects, Heater and Temperature Controllers, Sensors and Detectors

Light Controlled Switch Circuit using IC LM311 and LDR

Last updated on 19 June 2026 by Admin-Lavi Leave a Comment

This article talks about Light Controlled Switch Circuit using IC LM311 and LDR, as it simple and very useful and it feel light change near it. We find this circuit in many place like automatic light, street lamp and security system and main thing is about voltage comparator with LM311 IC. Then LDR sees light […]

Filed Under: Automation Circuits, DIY Projects, LDR Circuits, LED and Lamps, Sensors and Detectors

Simple Dark Sensor Circuit with Buzzer

Last updated on 19 June 2026 by Admin-Lavi Leave a Comment

The Simple Dark Sensor Circuit with Buzzer is an easy project to build because it detects the absence of light and activates a buzzer, moreover, users can apply it in night lights, security systems and alarm circuits. Here, circuit works with LDR, 555 timer and buzzer, as low light makes buzzer ON. Furthermore, this circuit […]

Filed Under: 555 Timer Projects, Alarm Circuits, Automation Circuits, Mini Projects, Sensors and Detectors

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