Name_________________________
Exercise 3
The Protoboard: Vertical Connections
Purpose
The purpose of this exercise is to further familiarize you with the protoboard.
Objectives
After completing this exercise, you should be able to:
1.
Determine the patterns of conductive paths in the protoboard.
2.
Appropriately select the resistance range for the ohmmeter.
3.
Accurately read resistance values from the ohmmeter.
Lab Preparation
Review Section 4.5 of Fundamentals of Electronics: DC/AC Circuits.
Materials
1 trainer with hookup wires as needed
1 VOM with test leads
Discussion
You will now continue your examination of the protoboard to discover how the remaining vertical
holes are laid out electrically. The same measurement techniques that you used to investigate
the protoboard buses will be used to check out the rest of the board. Figure 3.1(a) is a
simplified illustration of the protoboard showing the rows of connection holes that will be tested
to verify either continuity or isolation (no connection) between them. The connection holes
extend outward from the recessed center dividers. Each small row contains five connection
holes that are electrically connected by a metallic conductor as seen in Figure 3.1(b). The
metallic conductor connecting the holes is imbedded in the plastic of the board so it is not
visible. Even though it cannot be seen, its presence can easily be verified electrically with an
ohmmeter. Each row of five connection holes is electrically isolated from all the others. This
will also be verified by using the ohmmeter.
Figure 3.1
The holes of the protoboard are arranged in rows, and their purpose is to enable you to
insert wires into them to make electrical contact. Underneath the holes, within the plastic
material, are metallic conductors. The metallic conductors interconnect the holes in patterns to
make groups of connection points, around which you can build electrical circuits. The holes
serve as electrical connection points that receive wires and gently clip onto them to hold them in
place.
Procedure
1.
Use the same short lengths of hookup wire that you used in Exercise 2.
2.
Insert the six test wires into the protoboard at the locations shown in Figure 3.2.
The test wires will serve as test points for the electrical tests that follow.
Figure 3.2
3.
Select the appropriate resistance range on the ohmmeter. Connect the ohmmeter to test
wires 1 and 2. Because they are inserted into the same row, there should be electrical
continuity between them. Does the ohmmeter indicate 0 ? _________
4.
Connect the ohmmeter to test wires 3 and 4. Would you expect to find continuity between
them?
What does the ohmmeter indicate? _______
5.
Connect the ohmmeter to test wires 1 and 3. These test wires are adjacent to one
another, but they are located in different rows. There should be no continuity between
these test points. What does the ohmmeter indicate? _________ 
6.
Connect the ohmmeter to test wires 3 and 5. These test wires are also adjacent to one
another but are in different rows. What does the ohmmeter indicate? ________ 
7.
Connect the ohmmeter to test wires 2 and 4. These test wires are adjacent to one
another, but they are located in different rows. There should be no continuity between
these test points. What does the ohmmeter indicate? ________ 
8.
Connect the ohmmeter to test wires 4 and 6. These test wires are also adjacent to one
another but are in different rows. What does the ohmmeter indicate? _________ 
9.
Finally, connect the ohmmeter to test wires 5 and 6. These wires are installed in the same
row, so electrical continuity between them is expected. What does the ohmmeter
indicate? ______ 
10.
Repeat the preceding steps for other rows on the protoboard.
Questions
1.
What did you discover when testing the other rows on the protoboard?
2.
What is the purpose of the recessed center divider?
3.
Describe in your own words how the protoboard connectors are physically and
electrically laid out.