Specifications: The APV414EH is a Normally Closed (1 Form B, SPST-NC), high-voltage PhotoMOS SSR in an SMD-6 package. It is rated for 120mA at 400V AC/DC. It has a 20Ω on-state resistance, provides 5000Vrms isolation, and features switching times of 20μs (turn-on, which opens the circuit) and 500μs (turn-off, which closes the circuit). It operates from -40°C to 85℃ with a 1.2-1.4VDC input. Application Scenarios: Specifically designed for fail-safe applications at high voltages where the load should be powered by default. Common uses include high-voltage safety interlock and emergency stop (E-stop) systems, alarm triggers in high-voltage equipment, watchdog timer circuits for power supplies, and any application requiring a guaranteed conductive path in high-voltage circuits unless actively switched off by the control circuit, in a surface-mount package.