Switching performance — load current and on-resistance
Rated for 500 mA continuous load current across a 0 V to 60 V AC/DC range, the AQY212SZ handles low-to-moderate signal and power switching — think solenoid valves, indicator lamps, or small motor loads in test equipment or industrial controls. Maximum on-state resistance is 2.5 Ohms, which sets the voltage drop at full load to about 1.25 V — acceptable for most logic-level loads but worth checking if the downstream circuit is sensitive to series resistance.
The SPST-NO (1 Form A) circuit means the relay is normally open — the load path closes when the input LED is forward-biased. No moving contacts, so no contact bounce or wear; the PhotoMOS solid-state switch handles the AC/DC output directly.