Nuts and Volts - October 2015

Ihad also started a small ship-to-shore electronics ervice business along with the above. With this array of devices waiting for repair, I was literally drooling over high quality test equipment to make my job easier, but school tuition pretty much kept my back to the wall financially. So, I had to do with what I had, or design and make up barebones test gear on my own. Bottom line is that I never lost my love or desire for quality test equipment.

The other reason was that in designing my own equipment or eventually buying commercial equipment, I was blown away by the quality of workmanship and cleverness of design. As far as I was concerned, quality test gear design and construction was the yard stick by which all other circuits were measured.

As time passed, my interest increased further in this area, mainly due to the design challenges it presented and the rewards of completion. A couple of years later and as luck would have it, I was hired by an R&D company that specialized in test equipment design and prototyping. As the old saying goes, “ I never had to work another day in my life.” Now, I am not trying to say that test equipment should be the ultimate goal in your electronics interest. However, once the initial architecture is laid out for any design, test equipment will be required for both the starting point and ending point for those projects. It all comes down to standards and a point of reference (try building a house without the use of a tape measure or level).

Since I have written many articles on test equipment construction, I thought I would back-track this time and look at this from a different perspective: Why do we need TE (Test Equipment)? What variety of TE do we require? What is the best progression of adding TE? And, last but not least, what are the economics of arriving to a fully equipped test bench?

I will address all these issues as sanely as possible based on my 40 years of building, acquiring, and using TE. This article will be mainly pointed towards analog electronics, but much of this spills over to digital use as well. Even with digital design and when all the “number crunching” is completed, it still comes down to analog electronics. This is especially true with ever-increasing speeds now employed — not to mention I/O ports to the real world such as sensors, etc. In reality, there is only one wave shape in the physics of electronics: the pure sine wave — which is analog!

All other wave shapes are an algebraic addition of many sines waves added together versus time. For example, a perfect digital square wave is really derived from a fundamental sine wave and all its odd harmonics (hundreds to thousands) that have decreasing amplitude with each increasing order of harmonic content — again, analog! (Be sure to check out Richard Agard’s article on harmonics in this issue.)

All in all, I can hardly imagine an electronics enthusiast without some sort of test bench. This can be as simple as a folding table and a couple of hand tools, along with a cheap DMM (Digital MultiMeter). Or, it can be as elaborate as a spare room just loaded with TE and a full complement of tools and accessories to go with it. This wide span of facilities depends on which direction(s) your hobby takes you, how deeply you get into it, and the years of involvement.

Interestingly, a lot of top rated engineers in the past all had very elaborate setups right in their own home. Most of them agreed that some of their best ideas originated there due to a quieter and more relaxing atmosphere than the typical workplace. So, location in your own home is something to keep in mind.

So, why do we need test equipment in the first place? Well, for a multitude of reasons, such as initial design and prototyping of the circuits we build; final adjustment and

Any of you that have followed my N&V articles over the past 10 years certainly know by now that I am a test equipment freak. This stemmed from a couple of reasons. Early on in getting my start in electronics and while still in the process of getting my education, I did what many other students were doing at that time — dabbling in radio and TV repair. This not only produced a small income to help with tuition fees, but also gave us invaluable hands-on insight to the actual working conditions of various circuits.