The AQY212GH is a 4-pin PhotoMOS relay designed for high-capacity switching with a continuous load current of 1.1 A and reinforced insulation providing 5,000 V AC I/O isolation voltage. This compact DIP package device features an on-resistance of 0.34 O (typical) and operates with an LED forward current of 5 to 10 mA in the recommended operating range. The relay exhibits fast switching characteristics with a turn-on time of 1.3 ms (typical) and turn-off time of 0.1 ms (typical), along with low off-state leakage current of 1 µA maximum. It operates reliably across a temperature range of -40°C to +85°C and is commonly used in measuring instruments, security systems, and alarm devices where electrical isolation and high switching capacity are required.