A simple circuit that measures relative intensity of two light sources

摘要

Question: Can I measure the difference between two light sources with an instrumentation amplifier?Answer:Yes, by replacing the main setting resistor of an instrumentation amplifier with two photoresistors.In many lighting applications, measuring the relative intensity of two light sources is more important than measuring their individual intensity, ensuring same intensity light sources. For example, it is helpful to compare the brightness inside a control room to a second room in the same building so the adjustment can be made any time of day or night, or bright light conditions are kept constant in a production system.