Nuts and Volts - December 2008

from our immediate discussion, you can put that circular saw away as we won’t be screwing down any of our electrical components into a slab of pine. We’re about to delve into some 21st century breadboarding.

If you’ve ever shopped for project parts at RadioShack, you are already familiar with their breadboards. RadioShack calls them perfboards. We’ll call them breadboards. An example of a RadioShack breadboard caught the attention of my camera in Photo 2. The phenolic RadioShack breadboard depicted in Photo 2 is most likely designated as FR-2; FR in this case indicates it is flame resistant and 2 is telling us that the perfboard is made of synthetic resin bonded paper.

Other than being rated as FR-2, the phenolic breadboard in Photo 2 is single-sided. That is, it presents unplated copper pads on one side only. Since there is only copper on one side of the board and there is no plating on the copper pads, a plated-through pad cannot exist on this breadboard. Thus, the RadioShack breadboards are equivalent to a single-layer printed circuit board (PCB) with no plated-through holes. These boards work very well for general-purpose breadboarding of standard leaded components. Some of the breadboards can also handle the mounting of SMT components if you choose a suitable copper pad arrangement.

If you don’t have access to a local RadioShack, you most likely use mail-order electronic vendors such as ( www.jameco.com) or Mouser ( www.mouser.com) to get your electronic parts fix. You will find a breadboard for almost any application within the pages of their catalogs. For instance, you’ll find a large selection of breadboards constructed using epoxy resin. These glass/epoxy breadboards are normally designated FR- 4. The number 4 signifies that the PCB material is composed of woven glass reinforced epoxy resin. An FR- 4 breadboard posed for Photo 3. The good news is that all of the basic techniques associated with breadboarding can be performed equally as well with an FR-2 breadboard as they can with an FR- 4 breadboard. However, a breadboard with plated-through holes does have its advantages.

wire is insulated, it must be stripped at both ends to expose enough of the wire to attach and solder it to each end of the electrical connection. Cutting, stripping, positioning, and soldering wires make up the bulk of breadboarding work. All of the mail-order electronics outlets and local RadioShacks offer electronic hand tools to help you with manipulating breadboard wiring. I have also found that local home centers stock high quality wire cutters, lead cutters, and pliers that work well in the breadboarding environment. Since good solder joints are a must for point-to-point electronic assembly, I suggest investing in a good quality soldering station. Check the pages of Nuts & Volts and you’ll find a number of vendors that can help you put a reliable soldering station on your bench. The bottom line in tool selection is quality. I know from experience that when those cheap lead cutters go dull in the middle of an important breadboarding project, you’ll wish that you had spent that extra couple of dollars for a higher quality tool.

Breadboarding 101

I’m not going to insult your intelligence by detailing the process of mounting a component on a breadboard and wiring it in. However, I will pass along some breadboarding wisdom:

• Rats nest wiring techniques insure breadboarding failure.

• Poor component layout insures breadboarding failure.

• Sloppy soldering techniques insure breadboarding failure.

• Never begin a breadboarding project until you have all of the components in hand.

• Route your breadboard wiring as if you were

■ PHOTO 3. This FR- 4 breadboard consists of 0.046 inch diameter plated through-holes, which are dispersed on 0.1 inch centers. The through-hole solder plating enables electrical continuity between both sides of the breadboard at every hole. Thus, this breadboard can be considered as double-sided with plated through-holes.

Tooling Up

The goal of breadboarding is to mount electronic components on a supporting substrate and make all of the necessary electrical connections that result in a functional electronic device. In most cases, a length of wire is used to make an electrical connection between components mounted on a breadboard. Before the wire is installed in the circuit path, the wire must be cut to length and if the