Experiment 12: Joining Two Wires Together
104 Chapter 3
Loudspeaker
To complete the project in Experiment 15, you’ll need a loudspeaker small
enough to fit inside your project box but louder than the 1-inch speaker
that you used previously. It should be 2 inches or 2.5 inches (50 to 60 mm)
in diameter. If you can find a 100Ω speaker, it will give you more output,
but an 8Ω speaker will be acceptable.Experiment 12: Joining Two Wires Together
Your adventure into soldering begins with the prosaic task of joining one wire
to another, but will lead quickly to creating a full electronic circuit on perfo-
rated board. So let’s get started!
You will need:- 30-watt or 40-watt soldering iron
- 15-watt pencil-type soldering iron
- Thin solder (0.022 inches or similar)
- Medium solder (0.05 inches or similar)
- Wire strippers and cutters
- “Helping hand” gadget to hold your work
- Shrink-wrap tubing, assorted
- Heat gun
- Something to protect your work area from drops of solder
Your First Solder Joint
We’ll start with your general-duty soldering iron—the one rated for 30 or 40
watts. Plug it in, leave it safely in its holder, and find something else to do for
five minutes. If you try to use a soldering iron without giving it time to get fully
hot, you will not make good joints.
Strip the insulation from the ends of two pieces of 22-gauge solid wire and
clamp them in your helping hand so that they cross each other and touch each
other, as shown in Figure 3-31.
To make sure that the iron is ready, try to melt the end of a thin piece of solder
on the tip of the iron. The solder should melt instantly. If it melts slowly, the
iron isn’t hot enough yet.Soldering Irons Get Hot!
Please take these basic precautions:
Use a proper stand (such as the one
incorporated in your helping hands)
to hold your soldering iron. Don’t
leave it lying on a workbench.
If you have infants or pets, remember
that they may play with, grab, or
snag the wire to your soldering iron.
They could injure themselves (or you).
Be careful never to rest the hot tip
of the iron on the power cord that
supplies electricity to the iron. It can
melt the plastic in seconds and cause
a dramatic short circuit.
If you drop a soldering iron, don’t be
a hero and try to catch it. Most likely
you will grab the hot part, which
hurts. (I speak from experience.)
When you burn your hand, you will
instinctively let go of the iron, so you
may as well let it drop freely without
the intermediate step of burning
yourself while it’s on its way to the
floor. Naturally, you should pick it
up quickly after it does hit the floor,
but by then you will have gained the
necessary time in which to make a
sensible decision to grab it by the
cool end.
Always bear in mind that others in
your home are more at risk of hurting
themselves on a soldering iron than
you are, because they won’t know
that it’s hot. Most soldering irons
have no warning lights to tell you
that they’re plugged in. As a general
rule, always assume that a soldering
iron is hot, even if it’s unplugged. It
may retain sufficient heat to burn
you for longer than you expect.