The Colossus Rebuild Project by Tony Sale

Colossus Reborn

The Thyratron ring control panels

The problem was to extinguish a Thyratron when the next one in the ring was struck by a sprocket pulse.

Tommy flowers devised a bi-phase circuit to do this with the anodes of alternate Thyratrons connected to the two phases. A very complicated circuit, and here it is:

This took me ages to get this working in 1996, but as the war time engineers remembered, when it was working it was very reliable.

Unfortunately most Lorenz wheels had a an odd number of elements so this was handled by another large chunk of circuitry with the odd Thyratron, V46, mounted on this ring control plate.

This page was originally created by the late Tony Sale, the original curator of the Bletchley Park Museum, and Secretary of the Bletchley Park Heritage Society.