If you needed to access the hole
to the right of the middle pin (the
one I covered with solder), you could
use a piece of solder wick to remove
the excess solder.
9. Following the above steps,
solder the remaining SMDs in place.
Figure 9 is a photo of my completed
board, on which I did remove the
excess solder that was covering hole
E4. Also, you can clearly see that I
didn’t perfectly position the right-most 1206 22K resistor, but again,
the circuit would work fine.
When you have completed your
board, you may want to test it for
accidental shorts between the various
pins. You can also check for the
correct resistances. Don’t forget that
there are two parallel resistors
between trace 1 and 2, so on my
board, I measured a 5K resistance
between those two traces.
■ FIGURE 9. Strip board completed.
in their design, including the DS3231
project that I mentioned earlier.
FINISHING UP OUR
Completing our multiplexed LED
project is simple; all we need to do is
construct a strip board that contains
the circuitry that we used in the
previous installment of the Primer.
Figure 10 shows a strip board
layout that will do the job. (A larger-sized version of the layout is available
at the article link.) The strip board is
very easy to construct, but there are
a couple of points that I need to
■ FIGURE 10. Strip board layout for multiplexed LED.