Staircase lighting circuit – schematic and installation diagrams

Design & TechnologyElectrical Engineering & SafetyAges 14–15

A staircase lighting circuit uses two two-way switches to control one lamp from two locations, with an optional intermediate switch added to control it from three locations. Students click each switch to toggle it, watch which wire is carrying current and whether the lamp is on or off, and switch between the schematic diagram (showing the switch terminals) and the installation diagram (distribution board, conduit, and ceiling lamp). The Check continuity button highlights the wire that is currently live and calculates the current I = P/U.