This British Standard specifies general design characteristics for lighting controllers to supply electric filament lamps used in aircraft instruments and for the illumination of panels, operating from nominal 28 V d.c. and 115 V a.c. 400 Hz aircraft supplies.
BS G 217:1975 history
0000 BS G 217:1975(2000)
1975BS G 217:1975 Specification for general requirements for cockpit lighting controllers