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get old, the voltage drops. If you get less than 5 volts from a 4-battery pack, it’s

time to get new batteries.

When a circuit doesn’t work, one of the first things to check is the voltage

between the +V bus and the ground bus of the breadboard. Here’s how:

1. Strip both ends of a 3" piece of 22 gauge wire.


2. Clip one end of each wire to one of your test leads.


3. Slip the free end of the wire attached to your red test lead into any
   contact on the +V bus.


4. Slip the free end of the wire attached to your black test lead into any
   contact on the ground bus.

Although you might not get a reading of the full 6 volts because of drain

on the battery from the circuit, you should get a reading above 3.5 volts.

If you get a reading close to 0 (zero) volts, check to make sure that your

battery pack and the wires from the battery pack terminal block are con-

nected properly.

Working with the Boxes that Contain Your Projects .................................

In most cases, you’ll want to put the breadboard on which you build your cir-

cuit into some kind of container. A container can make toting around your

breadboard easier, help prevent little bits from falling off, and make your pro-

ject look better. You might also want to add mechanisms for controlling your

circuit in a box. For example, you might operate a remote control device by

disconnecting and connecting wires on a breadboard, but wouldn’t it be easier

to put the breadboard in a box and then add switches and buttons you can

use to make it work?

In this section, we give you some advice about basic skills you need to work

with these containers for your projects.

Working with boxes..............................................................................

Essentially, using a box involves finding the right type of box and then drilling

or cutting holes in it to poke wires and items such as switches or speakers

through.

78 Part I: Project Prep