You are staring datasheet circuits the Application Note 028 Photomos Relays in pdf file that is listed in Library Reference datasheet archive category. This Application Note 028 Photomos Relays pdf file was obtained via www.panasonic-electric-works.se
Content : The Driving Circuit Controls The Photo Voltage And Thus The Transistors Switching The Output. Figure 2 Schematic Of A Photomos Relay . By Adding More Solar Cells