A4850 Solid State Relay, SPST-NO, 50 A, 530 Vrms, Panel, Screw. The A4850 is a panel mount Solid State Relay with screw termination. The series 1 zero voltage turn-on switching type solid state relay features SCR output for heavy industrial loads, aluminum baseplate, direct bond copper substrate, redesigned UL94 V-0 rated housing with anti-rotation barriers and improved SEMS screw and washer.