Hi Some of the “cheap" printed circuit board outfits are now economical enough that they are a pretty good way to, go even for a fairly speculative breadboard type circuit. You wind up with a double sided board with a good ground. That significantly reduces the guesses and gotcha’s. There have been numerous threads here on the list about who likes which vendor and just how cheap is cheap.
————— One example of a gotcha - ground bounce may be responsible for the odd behavior when switching from the Q to the Q bar output on the flip flops. Bob On Oct 14, 2014, at 12:34 PM, Simon Marsh <[email protected]> wrote: > Yes, I do understand I'm asking for trouble, though I kinda expected to see > more noise rather than less. > I guess its time to break out the soldering iron. > > Cheers > > > Simon > > On 14/10/2014 17:22, Robert LaJeunesse wrote: >> Using 74AC parts on what I think of as a pluggable breadboard (e.g. >> http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=2295705&MER=bn-me-ca-r1-best-sto-5) >> is asking for trouble. The parts are RF fast and the pluggable board has >> not very good contact resistance and certainly more inductance and shunt >> capacitance than is good for RF. I would highly recommend using dead-bug >> style on a solid copper plane, as provided by a chunk of unetched PCB >> material. (Jim Williams did a few like that, see >> http://1.bp.blogspot.com/-y3xQiBHHzaQ/UP3mLk96qWI/AAAAAAAAAss/ZvPbfN8lmTQ/s1600/eep114.jpg.) >> This approach allows for extremely short lead lengths and power supply >> bypassing (to the plane) with a near zero lead length capacitor. >> >> Bob L. >> >>> Sent: Tuesday, October 14, 2014 at 11:32 AM >>> From: "Simon Marsh" <[email protected]> >>> To: "Discussion of precise time and frequency measurement" >>> <[email protected]> >>> Subject: Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip >>> Flop >>> >>> ... 74AC74 ... knocked up on some pluggable breadboard >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
