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. […]
Sensors and Detectors
Temperature Based DC Fan Controller Circuit using Transistors
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 […]
Temperature Controlled Fan Circuit for Audio Amplifiers
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 […]
Light Controlled Switch Circuit using IC LM311 and LDR
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 […]
Simple Dark Sensor Circuit with Buzzer
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 […]
Automatic Night Lamp Circuit with Photocell
Automatic night lamp use photocell to check light or dark; when dark the lamp is ON and when light the lamp goes OFF. This type of circuit is good for street, garden and security lights and also the parts used in circuits are LDR (ORP12), op-amp (uA741), relay which controls the AC lamp. Also, low […]