[sdiy] Breadboards

[harrybissell]

Why I don't use breadboards - by H^) harry

When I was in college, a good friend of mine designed a circuit.
It was a theatrical light dimmer. Back in those dark days... many
theatrical light dimmers were still mechanical, or motor driven
rheostats
or variable transformers. There were some commercial thyristor designs,
but
they were still in their infancy. (no... they didn't use gaslights back
then :^)

The design was a voltage controlled dimmer. 0-10V in for full range
control.

He got a commercial prospect to come and see the design. Of course the
solderless breadboard chose that time to fail. He begged and pleaded...
just
five more minutes, it works I swear it does...  Well the guy gave him an
hour
to no avail.

Two hours later, he found a wire that had snuck through a gap in-between
rows
and shorted.

Two hours too late, too bad.  The opportunity was gone.

LOL... we had a small breadboard at work.  When we were forced to 'clean
the lab' I helped by offering to throw it away.  It was the ONE thing I
was sure we would never
miss :^P

SMT will certainly obsolete the solderless breadboard. Maybe SMT is not
ALL bad :^)
(it will obsolete my favored technique, vectorboard and T42-A pins)

If you like to use breadboards, that's cool. They were mainly used for
teaching
basic electronics in schools, so that parts etc could be re-used. Kind
of like what they
do with SPICE today.

Bob Pease made the following points in his book "Troubleshooting Analog
Circuits"

1) Capacitance: 2-5 pF between adjacent strips "On a good day, only a
wise engineer
could plan a layout that all the capacitors, sprinkled throughout the
circuit, wouldn't ruin"

2) Long leads : make adding effective bypass capacitors close to a chip,
difficult.

3) Plastics : esp Nylon, on warm humid days insulation resistance
suffers (too low).

4) Contamination : Solder scrapes off the leads and can build up causing
shorts.
The adhesive makes it difficult to blow the scrap away with compressed
air. (courtesy of Scott Bowman, Dublin CA.)

Bob concludes...

"I didn't even think about these solderless breadboards when I wrote my
series
because I see them so rarely at work. They just have too many
disadvantages
to be good for any serious work. So, if you insist on using these slabs
of trouble,
don't say that I didn't warn you."

The breadboards are like SPICE in many ways. They let you try an idea
quickly.
In either case... I would not trust a SPICE simulation until I had built
the real thing
and compared the performance (to improve both the circuit, and the spice
models).

Be afraid... be very afraid...   :^P

H^) harry