RARE COMPUTER HISTORY DOLLIS HILL RESEARCH LAB WHERE WW2 COLOSSUS WAS BUILT. The book is'The Industrial Application of Gas Filled Triodes' written by R. This book deals primarily with the hot cathode grid-controlled gas-filled triode (thyratron) and gives a detailed but easily understood summary of the operating characteristics and physical theory of this and allied tubes. As you can see from the stamp inside the front cover, this particular book came from the GPO research laboratory in Dollis Hill, where COLOSSUS, the WW2 code breaking computer was designed and built.
Many of these machines were built and they use THYRATRONS (Triode valves, filled with various gases) as high speed switches. A THYRATRONS is a type of gas-filled tube used as a high-power electrical switch and controlled rectifier. Thyratrons can handle much greater currents than similar hard-vacuum tubes.
Electron multiplication occurs when the gas becomes ionized, producing a phenomenon known as Townsend discharge. The 885 is a small thyratron tube, using xenon gas. This device was used extensively in the timebase circuits of early oscilloscopes in the 1930s. It was employed in a circuit called a relaxation oscillator. During World War II, small thyratrons similar to the 885 were utilized in pairs to construct bistables, the "memory" cells used by early computers and code breaking machines.
The 885 is a 2.5 volt, 5-pin based variant of the 884/6Q5. The rear bay of Colossus contained four racks, the R rack holding the staticiser and delta boards for the paper tape reader output and the K and S-wheel thyratron ring outputs, the M rack for the M-wheel staticisers and S-wheel motion logic.The very large W rack held, on one side all the thyratrons making up the wheel rings, 501 in all, and on the other side the 12 thyratron ring control panels. Also on the W rack were the link boards for the wheel patterns and the uniselectors for setting wheel start positions. The end rack of the back bay held the power packs. These were 50 volt Westat units stacked up in series to give +200 volts to -150 volts. The total power consumption was about 5 Kilowatts most of which was to the heaters of the valves. Please take a moment to read and understand my General Terms & Conditions, BEFORE proceeding. Only for high value, high weight, items this is not a problem, but NOT for small, low value items as it is not economically viable, and will not happen. Most of the items I have listed are VINTAGE, and have exceed their expected working life.
Do not use vintage parts in high risk situations that might hurt you, or others. Permission is not implied or offered. Please remember that vintage items, particularly electronic, mechanical and photographic items will have components that wear, and will need to be serviced as they will have parts that have lasted, far exceed their expected/planned/designed operational life.
This is why all non-new items are supplied on an'AS-IS' basis. All Vintage items, particular electronic and photographic ones are fragile. POSTING LARGE HEAVY parcels to foreign countries is both time consuming and expensive. We are very short on space.I don't like Tuesdays. There it is, I've said it. The item "RARE COMPUTER HISTORY DOLLIS HILL RESEARCH LAB WHERE WW2 COLOSSUS WAS BUILT" is in sale since Friday, September 23, 2016. This item is in the category "Computers/Tablets & Networking\Vintage Computing\Vintage Manuals & Merchandise".186" and is located in London, London. This item can be shipped to United Kingdom, to Austria, to Belgium, BG, HR, CY, CZ, DK, FI, to France, to Germany, GR, HU, to Ireland, to Italy, LT, LU, MT, to Netherlands, PL, PT, RO, SK, SI, to Spain, SE, to Australia, to United States, RU, to Canada, to Japan, to New Zealand, to China, IL, to Hong Kong, NO, ID, MY, to Mexico, SG, KR, to Switzerland, to Taiwan, TH, SA, ZA, AE, UA.