If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
... or maybe not.
I like large dynamic ranges, so browsing on Google maps or openstreetmap is quite fun, as with a few turns of the mousewheel I can go from seeing houses to the width of the Earth. Anybody that's noticed my gravity project will see that I'm aiming for a few more decades of range, the width of a hand to the radius of Earth's orbit, measuring gravitational attraction at both distances (coming on slowly).
Anyhow, spatial preamble over, now for time. I was raking through a box of ICs, looking for an LM324 for a minor project, and I came across a whole tube of HC393s. Now there is probably a 20 year wide band of engineers (containing me somewhere around the middle of the age range) who know vast numbers of 74 logic IC numbers without having to look them up, the way more sensible people know song titles or friends. This particular number is for a dual 4 bit ripple counter, which can be cascaded with a single link into a divide by 256.
In a reflective frame of mind, I dug out a 10MHz oscillator and a breadboard, and started cascading dividers, with a LED on each output.
The output of the third divider flashed at just under 1Hz, after a total division ratio of 16777216 (=256^3).
The fifth divider output will flash less than once per day, the sixth output slightly quicker than annually.
I will never see the seventh output turn on in my lifetime. I still wouldn't if I was starting from school rather than retirement.
Assuming power can be kept on the circuit, we will have had to move the Earth's orbit further away from the Sun* to see the output of divider number ten flash, as it grows into a red giant.
I continued putting the rest of the tube into circuit, getting to 20 cascaded dividers. I wondered how that second half of the dividers would feel, having been crafted from the finest zone refined silicon, never to see a clock pulse. Some theories suggest the universe would have decayed into black holes by the time the 20th would output a cycle.
* serious orbital engineering required, perhaps the capture a large asteroid or small planet and using it to slingshot Earth into a larger orbit, assuming mankind manages the comparatively minor engineering required to avert the Permian-Triassic-type warming event extinction that we seem hell-bent on creating (which I won't see play out, but some of you starting from school might).
Registered Member #4465
Joined: Wed Apr 18 2012, 08:37AM
Location: Bucharest, Romania
Posts: 145
When we see numbers bounce around like that, this would be simply defined as MTBF project. Actually should be stated MTTF (Mean Time To Failure) since the circuits are not repairable.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Master of the Universe
