GUVA-S12SD UV Sensor Module

In the circuit is visible the UV sensor, D1 type GUVA-S12SD, a Schottky type photodiode with gallium nitride, optimized for operation in photovoltaic mode.
The U1 chip is then visible which is one of the two operational amplifiers present inside the LM358 chip, high gain amplifiers, with internal frequency compensation, specifically designed to operate on a single power supply.
In other modules the integrated LM358 is replaced with the SGM8521 model which is always a Rail-to-Rail I / O CMOS operational amplifier.
See article https://www.adrirobot.it/sensore-uv-guva-s12sd-arduino/