Cambridge Aero mixture indicator

Rehlombard
It has taken me a while to locate the book that has all the detail you require.
In the book, Pilot’s and Mechanics Aircraft Instrument Manual, by G.C. DeBaud, The Ronald Press Co., New York, 1943, there is 18 pages on the Cambridge Aero Mixture Indicator. It goes into a lot of detail as to how it works, testing and trouble shooting, and how to connect for a variety of aircraft configurations.

The system works on the Wheatstone bridge principle. 2 legs of the bridge have identical platinum coils located in cells, one cell is connected to the exhaust and the other to a known gas located with in the cell.

A little more detail is described in this link.

http://www.tighar.org/forum/Highlights101_120/highlights105.html#17