As we progress in our acquisition of electronics skills, we occasionally reflect on the “shape” that our knowledge and skills are taking. This article is an overview of basic decisions that “sculpt” our know-how and some of the consequences of the shape of it.
In school, we make our first choice about where we will put our developmental efforts by electing an emphasis on certain topics. The basic alternative in the past (and continuing somewhat in the present) is whether to become an electrical or an electronics engineer. An electronics engineer is a kind of electrical engineer because the historic development of the engineering of electricity first involved electric power generation and transmission. Now, electronics is but one of several sub-fields, all under “electrical engineering”.
The widely-used metaphor is that knowledge is like a field with various positions within it representing different subject-matters. Like a mathematical field, it is capable of sustaining multi-dimensional functions with various peaks and valleys that characterize what we know and can do, or what we are ignorant of. Job interviews are an example of where explorations of the field of the job-seeker (and the interviewer) are conducted.
As we learn more, we have another choice: how “deep” do we go and where? A basic choice is to either become a specialist, an expert in one constrained area of knowledge-space, or a generalist, operating at less depth than the specialist though over a wider range. Did you notice the second metaphor - that of depth - a word so familiar that it has nearly ceased to be metaphorical and has become a part of the lexicon of knowing (epistemology)? Yet it is not a quantified variable.
Nobody responds to the question, “How much depth do you have in analog circuits?” by replying, “About 10 meters.” However, a semi-quantitative scale using an ocean metaphor might be of some benefit. There are actually two different metaphors for describing amount of knowledge, one depth and the other height. Staying with depth, the following chart offers a semi-quantification of depth of knowledge of subject-matter X, extending the metaphor to the ocean as the field of knowledge.
The deeper one wants to dive, the greater are the effort and persistence required to achieve expert knowledge. Consequently, such diving only occurs in a few places or even one selected place. In contrast, surface swimmers or snorkelers can easily go to any dive spot or beach for their activities. For bathyscaphe depth, the options are restricted. Some topics are exhausted more readily and knowledge-seekers reach rock bottom at SCUBA depth.
In the limit, a generalist knows nothing about everything with a range of knowledge that is broad but shallow. The best way to become a generalist is to gain substantial depth in a few different places, especially if they are synergistic. Likewise, a specialist in the limit knows everything about nothing. The best way to specialize is to have significant depth in one place while maintaining varying, though lesser, depth around the center of expertise.
In electronics, synergy can be achieved, for instance, by diving into power electronics with knowledge of analog circuits. Both depend on an understanding of control theory, and diving in both places puts control theory to multiple uses. Knowledge of digital signal processing can be applied to analog circuit design such as sample and hold circuits. Knowledge of magnetics from power electronics can be applied to analog communications circuits.
A somewhat unusual and interesting example of multiple dimensions of synergy is the case of Brian May, the lead guitarist of the considerably successful British ‘70s rock-music group, Queen. May had played the guitar since he was a child, but was also working toward his doctorate in astrophysics, studying the movement of dust in space. When the music group took off, he discontinued his doctoral research and became rich and famous. He is one of the best guitar players around. Then decades later, with his scientific interest still intact, he returned to his doctoral study to find that in the intervening years, nobody had paid much attention to space dust. He completed his old thesis and was awarded by Imperial College in London a PhD in astrophysics. NASA invited him to be a collaborator on the Pluto flyby, where he used another interest of his, stereo viewing, to create the first 3-D view of Pluto.
While he was primarily in the music world, he had considerable knowledge of physics and enough audio electronics to devise experimental setups to achieve new sounds. For instance, two tape players would be used to record delays. The first player would record, the tape would travel across the room to the second tape player, and it would play back the delayed sound. To avoid acoustic resonances, delays were based on prime numbers so that no harmonic multiples were invoked. Thus, his physics knowledge was used to make some of the “layered” sounds that characterized the group.
Additionally, while Queen was in their heyday, he wrote a song, ’39. He has commented that there have been various songs written for acoustic guitar about explorers going off in ships in search of new lands. His song was similar except that the explorers went off in a spaceship, and because of the relativistic effects of traveling near the speed of light, when they returned in a year, they encountered the grandchildren of the people they knew before they left. (“Your mother’s eyes, from your eyes, cry to me.”) When I heard May explain the song the first time, a flag went up in the back of my mind that this was no ordinary rock guitarist, invoking Special Relativity as the basis for one of his songs! Again, synergy was present in combining knowledge of music (song-writing) with astrophysics. May does a solo studio version of the song on acoustic 12-string guitar in the following YouTube video:
One of the NASA people also perceptively pointed out that May looks like Isaac Newton.
A good engineer (or astrophysicist/guitar virtuoso) manages where to put learning and skill-acquisition effort so that a synergistic effect results, multiplying instead of only adding to combined ability. Now for a synergistic challenge for May: to find a way to work the astrophysics of space dust into guitaring or audio recording!
The class-B push-pull transformer isolated power amplifier was very popular in portable transistor radios. When I started playing guitar my first amp was the output stage savaged from one old VEF-206 radio (from the former USSR). I only used it for studying. It was a very low power amplifier but provided nice undistorted and overdriven sounds, even small speaker and the awful guitar I had at that time.
That radio was very very popular at that time. My father still has several of them at home. These are some pictures from Inet:
Knowing that I am originally from Rhodesia, Michael Dunn sent this link to me about the "Deacy" amplifier that Brian may used. It appears that not all of Brian May's activities were based in theory! Aside from its country of origin in deepest darkest Africa, I think it is still interesting for all readers of Planet Analog.
This is a tutorial presentation of principles of instrumentation that is typically multi-channel, medium to high resolution (12 to 20 bits) and relatively slow - slower than oscilloscopes in sample rate
Continuing the chat from last time, we turn now to a circuit-related topic, that of current waveforms. The typical converter input waveform is shown with a static (dc) component and a ripple (ac) component
Semiconductor companies have now had fully-differential amplifiers in their product lines for a few years, though these amplifiers have been in leading-edge electronics for decades. These diff-amps are differential not only at their input but also at their output, doubling output range.