Make: Electronics by Charles Platt (classic books to read TXT) 📗

drop one of the boxes, it probably won’t open. The lids have metal hinges, and a ridge around the edge that makes the boxes securely stackable.

I keep my little storage boxes on a set of shelves above the desk, with a gap of 3 inches between one shelf and the next, allowing two boxes to be stacked on each shelf. If I want to work with a particular subset of boxes, I shift them onto the desktop and stack them there.

Labeling

No matter which way you choose to store your parts, labeling them is essential. Any ink-jet printer will produce neat-looking labels, and if you use peelable (nonpermanent) labels, you’ll be able to reorganize your parts in the future, as always seems to become necessary. I use color-coded labels for my collection of resistors, so that I can compare the stripes on a resistor with the code on the label, and see immediately if the resistor has been put in the wrong place. See Figure 5-6.

Figure 5-6. To check that resistors are not placed in the wrong compartments, print the color code on each label.

Even more important: you need to place a second (non-adhesive) label inside each compartment with the components. This label tells you the manufacturer’s part number and the source, so that reordering is easy. I buy a lot of items from Mouser, and whenever I open their little plastic bags of parts, I snip out the section of the bag that has the identifying label on it, and slide it into the compartment of my parts box before I put the parts on top of it. This saves frustration later.

If I were really well organized, I would also keep a database on my computer listing everything that I buy, including the date, the source, the type of component, and the quantity. But I’m not that well organized.

On the Bench

Some items are so essential that they should sit on the bench or desktop on a permanent basis. These include your soldering iron(s), helping hands with magnifier, desk lamp, breadboard, power strip, and power supply. For a desk lamp, I prefer the type that has a daylight-spectrum fluorescent bulb, because it spreads a uniform light and helps me to distinguish colors of adjacent stripes on resistors.

The power supply is a matter of personal preference. If you’re serious about electronics, you can buy a unit that delivers properly smoothed current at a variety of properly regulated and calibrated voltages. Your little wall-plug unit from RadioShack cannot do any of these things, and its output may vary depending on how heavily you load it. Still, as you’ve seen, it is sufficient for basic experiments, and when you’re working with logic chips, you need to mount a 5-volt regulator on your breadboard anyway. Overall, I consider a good power supply optional.

Another optional item is an oscilloscope. This will show you, graphically, the electrical fluctuations inside your wires and components, and by applying probes at different points, you can track down errors in your circuit. It’s a neat gadget to own, but it will cost a few hundred dollars, and for our tasks so far, it has not been necessary. If you plan to get seriously into audio circuits, an oscilloscope becomes far more important, because you’ll want to see the shapes of the waveforms that you generate.

You can try to economize on an oscilloscope by buying a unit that plugs into the USB port of your computer and uses your computer monitor to display the signal. I have tried one of these, and was not entirely happy with the results. It worked, but did not seem accurate or reliable for low-frequency signals. Maybe I was unlucky; I decided not to try any other brands.

The surface of your desk or workbench will undoubtedly become scarred by random scuffs, cut marks, and drops of molten solder. I use a piece of half-inch plywood, two feet square, to protect my primary work area, and I clamp a miniature vise to its edge. To reduce the risk of static electricity when working with sensitive components, I cover the plywood with a square of conductive foam. This is not cheap, but offers advantages in addition to protecting chips from being zapped. Instead of scattering stray components, I can stick them into the foam, like plants growing in a garden. And like a garden, I can divide it into sections, with resistors on one side, capacitors on the other, and chips straight ahead.

Inevitably, during your work you’ll create a mess. Little pieces of bent wire, stray screws, fasteners, and fragments of stripped insulation tend to accumulate, and can be a liability. If metal parts or fragments get into a project that you’re building, they can cause short circuits. So you need a trash container. But it has to be easy to use. I use a full-size garbage pail, because it’s so big that I can’t miss it when I throw something toward it, and I can never forget that it’s there.

Last, but most essential: a computer. Now that all data sheets are available online, and all components can be ordered online, and many sample circuits are placed online by hobbyists and educators, I don’t think anyone can work efficiently without quick Internet access. To avoid wasting space, I suggest you use a small, cheap laptop that has a minimal footprint. A possible workbench configuration, using a steel desk, is shown in Figure 5-7.

Figure 5-7. An old steel office desk can be as good as, if not better than, a conventional workbench when building small electronics projects. It provides a large work area and ample storage, and has sufficient mass for you to ground yourself when dealing with components that are sensitive to static electricity.

Reference Sources

Online

My favorite educational and reference site is Doctronics (http://www.doctronics.co.uk). I like the way they draw their schematics, and I like the way they include many illustrations of circuits on breadboards (which most sites don’t bother to do). They also sell