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Date: Mon, 16 Sep 2002 08:42:33 -0700
From: RP Henry
X-Mailer: Mozilla 4.75 [en] (Win98; U)
Subject: Re: Digital divide by ten, 1949 style
References: <3D84D4B3.50B511EF@webaccess.net> <3D84DB29.A73BF8B5@webaccess.net>
Chuck Simmons wrote:
> Chuck Simmons wrote:
> > Tim Shoppa wrote:
> > >
> > > 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_:
> > >
> > > http://www.trailing-edge.com/~shoppa/div10.png
> > >
> > > 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.
> > >
> > > Maybe they do cheat a little with respect to the previous thread; is a
> > > dual triode the 1949 equivalent of an IC? :-)
> > >
> > > Tim.
> > There were a lot of interesting techniques with magic bottles. The
> > counter pales before the all tube frequency synthesizers that came along
> > in the 1950s capable of 2 to 32 MHz in 100Hz steps.
> > The 6H6 dual triode dated from the late 1930s and was common in
> > commercial and military equipment but the 5 tube radio of the era was
> > inocent of the beast (if I recall, the 6H6 was a "metal" tube).
> > "MSI" came to tubes in the 1960s with the introduction of compactrons
> > that might have two triodes and a pentode or some such. I forget any of
> > the numbers of these but in reality, these were like ASICs in that they
> > really were optimized for particular applications in TV recievers. They
> > had little impact on the traditional dual triodes like the 12AX7 and the
> > 12AU7 and the garden pentodes such as the 6AU6. Actually, some
> > integration was not obvious. It seems to me the 6BE6 had 5 grids and was
> > ideal as a mixer in superheterodyne recievers such as radios and TVs
> > (there was a metal tube that was similar dating from the advent of the 5
> > tube radio).
> > Pin limitations on tubes were important in the 1920s and early 1930s, 6
> > pins was about the limit. A very common tube of the time, the 01-A had
> > but 4 pins. Power tubes and some pentodes had the anode brought out
> > through a contact at the top of the tube. The 417 and 723 local
> > oscillator klystrons had the repellor on such a contact. In the 1930s,
> > the octal, 8 pin keyed base, came along. Later power tubes expanded the
> > number of pins with the 826 dual power triode and even later the 829 and
> > 3E29 dual pentodes. In this era, miniature tubes had 7 or 9 pins (the
> > classic 12AX7 and 12AU7, still available today in some variant, had 9
> > pins).
> > The mid 1960s through the mid 1970's was very much transitional. I
> > designed stuff in that period that combined ICs, transistors and tubes.
> > My last tube design was essentially a quad operational amplifier with
> > more than a 10,000 volt output swing. If I remember correctly it was 19
> > inches wide and 11 and 3/4 inches high. It used ICs, transisters,
> > optoisolators (needed for totem pole output) and tubes (2 6BK4's per
> > opamp).
> > It has been very exciting to live through the progress from the
> > invention of the transistor in 1949 through the introduction of the
> > famous CK722 transistor to where we are today with millions of
> > transistors in a single package.
> > I firmly believe that the final demise of the tube as a common component
> > was due to the fact no one ever figured out how to build a P-channel
> > tube. :-;
> > Chuck
> Oops! The metal dual triode was the 6SL7. The 6H6 was a dual diode with
> common cathode (hence the extra tubes in the counter).
This source says common cathode heater, but separate signal diodes
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