Photoresistor can form a bridge photodetector circuit diagram

In industrial photoelectric measurement devices, photoresistors can form a bridge photodetector, as shown in the figure. Two photoresistors of the same model (equal dark resistance) are used as bridge arms, one of which is used for photoelectric detection, and the other is sealed with black tape to prevent it from receiving light and is used for temperature compensation. This bridge photodetector can operate with either DC or AC. When AC modulation is used, it outputs an AC signal, which can reduce the zero drift of the amplifier.