Page 439 - Robot Builder's Bonanza

408 USING SOLDERLESS BREADBOARDS

Rows
(for + and - power)
1 5 10
A
B
C Columns
1 5 10 15 20 25 30 D
A A E (for components)
B B
C C
D D F
E E G
H
I
F F J
1 5 10
G G
H H
I I
J J
1 5 10 15 20 25 30
Figure 32- 2 Underneath the holes in the
breadboard are strips of conductive metal
with spring contacts. Plugging a wire into a
Figure 32- 1 Solderless breadboard with 400 tie points. hole pushes the wire into the contacts.
discrete components like capacitors and resistors. The holes, called contact points or tie
points, are the proper size for 22- gauge solid conductor wire. On each column you can con-
nect together as many as five wires or components.
In addition to the column connections, many solderless breadboards have long rows on
the top and bottom. These provide common tie points for the positive and negative power
supply.
But from here, the size and layout of breadboards can differ greatly. Some measure a few
inches square and contain only 170 holes. The 170- tie- point boards are made for simple
circuits with one or two small ICs or a handful of small components. For bigger circuits you
need a bigger breadboard. You can pick among models with 400, 800, 1200, even 3200 tie
points.
Which size should you get? I believe in starting out small, the extra benefit being that small
breadboards cost less. They’re usually more than adequate for testing the typical robot control
or sensor circuit. You can always get a larger board as your needs grow.

MAKING CONTACT
The contact points are usually made from a springy metal coated with nickel plating. The plat-
ing prevents the contacts from oxidizing, and the springiness of the metal allows you to use
different- diameter wires and component leads without seriously deforming the contacts. How-
ever, the contacts can be damaged if you attempt to use wire that’s larger than 20 gauge.
(Remember: Wire gets bigger with smaller gauges.)

The more you use your solderless breadboard, the faster it’ll wear out. After a while, the springy
G metal isn’t so springy. Dust can settle inside the contact points and decrease the electrical
contact. This is another reason not to invest in a large and expensive breadboard. The cheap
ones don’t cost as much when they need to be replaced.

Things you should not try to plug into a solderless breadboard contact point include:

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