BCD counter

This contribution is based on my year 2000 paper called:

Some aspects of precision time measurements, controlled by means of piezo‑electric‑vibrators, as deployed in Germany prior to 1950

Arthur O. Bauer

Early efforts on electronic BCD counters (1940 - 1945)

A few years ago, Leonard Hunter brought to my attention the book entitled AGerman Research in World War II, an analyses of the conduct of Research@, by Leslie E. Simon published in 1947 (Colonel Simon was, at the time, in the Ordnance dept. and was US Army director of the Ballistics Research Lab.). This most interesting survey describes in detail the wartime German Army and Air Force research and development centres. Due to Simon=s comprehensive knowledge about the state of the art in both the US and the German research establishments, he passes on to the readers a most thorough inside view of what was going on. I became fascinated by his description of an electronic chronograph which he came across at the German Army proving ground at Hillersleben. This must have been an unique piece of equipment. If similar equipment had been available on the allied side I am sure he would have mentioned it!

This device had been manufactured by the Berlin(er) Physikalische Werkstätten at Immenhausen. I have researched the background of this company which, as far as I could find out, was established a long time ago and produced mainly laboratory instruments for educational purposes. However, this firm=s name appears on some patent applications relating to more sophisticated apparatus as well. There is evidence that this company became the contractor for various special projects. It was established in Berlin W 35 in the Woyrchstrasse 8. But adding the term AGmbH@ suggests that it was either owned or affiliated to another company (due to its limited legal liability).

The counter chronograph, or, properly counter chronoscope, is an electronic device for counting electric cycles with extreme rapidity. A fixed frequency, say 100,000 cycles per second, is supplied by a crystal oscillator. The counter starts at a signal such as the passage of a bullet through a pick-up screen, and stops on a similar signal. In simple form, the counter is equipped with a vacuum-tube circuit which functions as follows: on receipt of the first cycle after the start signal the circuit causes the first of a series of small neon lamps to glow; the second cycle extinguishes the first lamp and excites the next one; the third cycle again excites the first lamp; the fourth cycle extinguishes the first lamp and the second lamps and excites the third, and so on. Successive lamps, when glowing, represent 1, 2, 4, 8, 16, 32@ @ @ @2^n-1 cycles, and the total numbers of cycles in any recorded period is equal to the sum of the numbers corresponding to the lamps found glowing at the end of the time interval. In some counter chronoscopes the lamps are arranged in groups of four and the circuits are designed to reset each group to zero after the ninth count in order to give numbers in the decimal system.