Make Electronics

Switching Basics and More 45

Experiment 6: Very Simple Switching

Figure 2-20. To remove insulation from
the end of a thin piece of wire, you can
also use wire cutters. This takes a little
practice.

Figure 2-21. Those who tend to misplace

tools, and feel too impatient to search for

them, may feel tempted to use their teeth

to strip insulation from wire. This may not

be such a good idea.

Connection Problems

Depending on the size of toggle switches that you are using, you may have
trouble fitting in all the alligator clips to hold the wires together. Miniature
toggle switches, which are more common than the full-sized ones these days,
can be especially troublesome (see Figure 2-22). Be patient: fairly soon we’ll
be using a breadboard, which will eliminate alligator clips almost completely.

Testing

Make sure that you connect the LED with its long wire toward the positive
source of power (the resistor, in this case). Now flip either of the toggle switch-
es. If the LED was on, it will go off, and if it was off, it will go on. Flip the other
toggle switch, and it will have the same effect. If the LED does not go on at all,
you’ve probably connected it the wrong way around. Another possibility is
that two of your alligator clips may have shorted out the battery.

Assuming your two switches do work as I described them, what’s going on
here? It’s time to nail down some basic facts.

Figure 2-22. Miniature toggle switches can

be used—ideally, with miniature alligator

clips—but watch out for short circuits.