Soeren said:
Hi Terry,
Yup
I guess you are one of the build-first-make-drawings-later kind of guys ?
Well, I hope your designs are beter than your guesswork, then! You
haven't been around these groups long, it seems, or you'd probably
have guessed better.
I guess you're one of these guess-now-find-the-rationale-later kind of
guys?
Like most of my designs, this was drawn first (and simulated) and
*then* successfully breadboarded. But the initial schematic didn't
include the lamp and relay, just the logic. Not sure what ECAD program
you use, but CircuitMaker, like several others I know of, doesn't
require an explicit Vdd line for hybrid circuits like that one.
On later preparing the finished schematic I thought I'd better add
some token caps to the supply line, and carelessly hung them on that
convenient horizontal line as you saw. It was then easy to take my
buzzer to the same node too! In mitigation, my wife was calling me
down to dinner at that time... said:
Even if you are, build after the schematic when it is finished, or better,
let somebody else build it up, it will catch all these drawn-late-in-the-
night errors
Just a tad patronising? But, even if I felt I needed such reassurance
for a simple circuit like this, I don't normally have a 'somebody
else' permanently on hand with the requisite skills. Do you?
Does your circuit actually work, BTW?
Not except that you cannot adjust the timing and you have to use a buzzer
instead of a cheaper "loose" piezo disk
OK, but timing was covered by my footnote. And Zhanglu never answered
my specific question about the type of 'beeper'. Unless he enlightens
us now, we'll never know if my assumption that it's a DC-powered
device was correct.