Hi Yes indeed.
A lot of this was worked out a very long time ago. Most of what you see on the net these days is simply an IC circuit broken out into a bunch of discrete parts. IC's have different issues than discretes. Bob On Jan 8, 2010, at 10:46 PM, Bruce Griffiths wrote: > > At high temperatures the circuits with the additional diodes in series with > the base will have problems with transistor leakage currents when all inputs > are low. > The person who created that page doesnt know how to design reliable circuits. > A base to emitter shunt resistor is one way of avoiding this problem. > > Bruce > > Stanley Reynolds wrote: >> Knowledge of history doesn't = having lived it :-) >> >> http://www.play-hookey.com/digital/electronics/dtl_gates.html >> >> 3 to 1 is not all that odd if you have 5 to 1 and 2 to 1 ratios as the page >> above indicates. >> >> Stanley >> >> >> >> ----- Original Message ---- >> From: Bob Camp<li...@cq.nu> >> To: Discussion of precise time and frequency measurement<time-nuts@febo.com> >> Sent: Fri, January 8, 2010 8:10:34 PM >> Subject: Re: [time-nuts] Digital Clock kit - no Integrated circuits! >> >> Hi >> >> It seems like the diode to resistor ratio is a bit off in that design. >> >> In order to go into further detail, I would have to admit to starting out in >> the pre-integrated circuit logic era .... >> >> Bob >> >> >> On Jan 8, 2010, at 8:07 PM, Tom Clifton wrote: >> >> >>> http://transistorclock.com/ has a very interesting (though a bit >>> expensive) kit for sale. A 10" x 11" circuit board sporting nearly 200 >>> transistors and 600 diodes to drive six seven-segment displays. Suitable >>> for framing... As delivered runs on 60hz but there is a note about >>> conversion to 50hz mains. You can buy a bare board, just the components >>> or a full kit. >>> >>> You must see it to believe it! >>> >>> Tom >>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.