The circuit will show visual indication of light intensity with LEDs. This is an essential project for electronics LAB to measure the light intensity of different LEDs, lasers and other light bulbs. The circuit can be used for many other varieties of light intensity measurement purposes like solar experiments etc.
As discussed above the circuit is using two LM324 ICs. LM324 is a quad operational amplifier IC. Each IC contains four totally independed opamps. In this project we have used all the four opamps of both LM324 ICs, the 10K variable resistors separately controls the output of each opamp.
An LDR is used as a light sensor in the circuit. You can also experiment other light sensing devices for example mini solar cell, phototransistor etc. you can also experiment with different values of the R9 or use a variable resistor in the place of R9.
The operating voltage of the circuit is 5V to 12V DC. If you are operating the circuit with below 9 volt then replace all the 470 ohms resistors with 270 ohms or 330 ohms.
We cannot detect the minor differences or changes in the intensity of light due to which we have to use a LUX meter for light intensity measurements. This article describes project of a light intensity meter or LUX meter that can be easily made with two LM324 ICs and few other discrete components.
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