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 diagram illustrating four different electrical circuit configurations.
| Identifier | ExFiles\Box 65\2\ scan0052 | |
| Date | 30th January 1930 guessed | |
| 2 2R 2 2R 2 2R 2 2 2 2R 2 2R FIG 1. FIG 2. FIG 3. FIG 4. | ||