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From: firstname.lastname@example.org (Carl Lowenstein)
Subject: Re: Digital divide by ten, 1949 style
Date: 21 Sep 2002 16:02:54 -0700
Organization: Marine Physical Lab
NNTP-Posting-Date: Sat, 21 Sep 2002 23:03:05 +0000 (UTC)
In article <5f4h9.19590$S32.email@example.com>,
>"Tim Shoppa" wrote in message
>> In a recent thread on sci.electronics.design, we explored some approaches
>> to divide-by-ten without using IC's. (Go to http://groups.google.com/ and
>> search for "Decade counter without IC's"). Here's an approach I found
>> in Vol. 19 of the Radiation Laboratory Series, _Waveforms_:
>> They do it with just ten tubes, and the output is BCD on 4 neon bulbs.
>> Comments on similar counters would lead me to believe that the design is
>> good to a few MHz.
>At least one ring oscillator (called a ring counter) appears in Markus and
>Zeluff, from a 1946 Electronics article about a different circuit. What's
>the earliest ring oscillator anyone has heard of?
When I was taking an Electronics course in college (1953) one of
the lab demonstration pieces we had was a divide-by-5 ring counter.
For authenticity, the Professor had instructed some former students
to construct this counter exactly as it had been published in a
physics journal. Thus it used type 57 pentodes (2.5V heaters) which
dates the design to before the popularity of 6V car radios and tubes
with 6.3V heaters. That must date the design to the late 1930's at best.
Of course, we didn't have a 2.5V source to run it from, so it was
connected between one side and centertap of a 6.3V supply.
The type 57 metamorphosed into the 77 and then the 6J7 and then the 6SJ7.
carl lowenstein marine physical lab u.c. san diego
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