By Bryan Bergeron View In Digital Edition
When I started out in electronics, my “junk box” of rescued parts from TVs, radios, and the like was the source of endless projects and test instruments. Armed with a few key texts — especially the ARRL Handbook and Getting Started in Electronics by Forrest Mims — just about anything was possible. Sure, my projects didn’t win any beauty contests with labels made with a permanent marker and reused chassis with dozens of extra holes, but most worked — eventually. It’s the “eventually” part that’s key.
I can recall dozens of blown circuit breakers, exploding electrolytic capacitors, and shorted vacuum tubes. However, I also recall the satisfaction of seeing copper, carbon, and steel come to life.
With time and savings, I later could buy just about anything that I wanted — from commercial test gear to top-of-the-line ham radio equipment. It made for a great looking test bench and ham shack, but I lost out on the learning end of things. It didn’t matter that I could read the schematic of the hermetically sealed phase locked loop synthesizer in my communications transceiver — I could never really know it. I could replace it if defective, but not really fix it the way I could one of my old creations.
From a practical perspective, having a nice portable o-scope with high bandwidth and Flash memory storage makes debugging a pleasure. Then, there’s the safety issue — none of my creations were UL listed or approved.
So, there’s nothing wrong with new gear that’s compact, safe, and easy to use. It’s just that — from an experimenter’s perspective — shiny commercial equipment can become a black box. I make a habit of disassembling everything I buy; in part to understand what’s in the black box, but it’s still an imperfect exercise.
If your goal is to maximize the learning experience — whether for yourself or someone you hope to pass on your knowledge of electronics to — then I’d consider the old school “junk box” approach to learning. Fill your box with parts from tear-downs of whatever you can get your hands on. It’s amazing what you can harvest from an old PC, for example. Even a discarded compact florescent bulb can yield a half dozen reusable components.
I’m fortunate to live a few miles from MIT, where there’s often a flea market of used test gear and lab equipment that’s sold by the pound. Find out where your local ham or flea market is held and drop by at least once a year. Even if you don’t use parts harvested from the gear to build your own, the exercise of a tear-down is educational in itself.
You can’t wildly rip things apart, however. Take a methodical approach, trace the connections to see what components are associated with each other and — if you can — create a schematic diagram of the circuit in the device.
Lately, I’ve been partial to vacuum tube projects. With a few tubes and high voltage power supplies on hand, it doesn’t take much effort to build oscillators, tuners, sound effects devices, and so on. So, go ahead. Give the “old school” junk box method of setting up your workbench and your communications, robotics, or other projects a try. Your projects may not look as attractive as the commercial systems, but you’ll really understand the inner workings of what you build.
You’ll then be well on your way to being a real experimenter. NV
