13 Jul
2007
13 Jul
'07
11:06 p.m.
dwight elvey wrote:
Hi Bret
I recall that is was an HP counter. I don't recall the fastest count but
it was on the order of either 10KHz or 100KHz. I don't think it was
less then that but it may have been 1MHz. I recall that like many of the
HP counters of the time, the other decades were the inline 10 ea bulbs. I
don't recall if these were neon or incandescent but I think they were
neons driven by dual triodes. I do believe that the ring counter did
have a purplish glow.
Dwight
I have the manuals for most of the early HP counters. I looked through
them and could not find
dekatrons used. The input goes directly to the counter units. The 523C
goes to 1.2 MHz.
In the 524B counter, there are two divide by 10 circuits built with tube
flip-flops. This
counter counts up to 10 MHz.
In the timebase circuit, they used a two tube circuit called a
phantastron to divide the 100KHz
crystal down. The circuits are decade dividers. In the 523C counters,
the tubes are
1/2 of a 6AL5 diode and a 6AS6. They work up to at least 100KHz.
A circuit and description can be found here:
http://www.dvq.com/images/phantastron.jpg
The odd thing about this is I swear I remember the ring counters also. I
don't remember a purple
glow, just the typical red-orange. I'm still looking through manuals to
see if I can find something.
Bob
