From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Hand-drawn wiring diagram of an ignition circuit with a change-over switch.
| Identifier | ExFiles\Box 168a\2\ img420 | |
| Date | 5th April 1939 guessed | |
| +, IGN SWITCH, BALLAST, COIL, HT, LT, CHANGE OVER, SWITCH | ||