2011 Issue

27 W ELL–WhAT we do know is that most are obsolete, for example – ana- log circuits, the backbone of old electronics. But should they be? This note resurrects an example as applied to current problems and progress. One action the US took in anticipation of WWII was to establish the Radiation Laboratory (RL) at Massachusetts Institute of Technology (MIT) in November 1940. Its charge was to develop microwave radar – and quickly! That was done and it proved to be effective in winning battles - land, sea and air. The first staff members were the experts of nuclear physics and the elite of top universities. Half of them later went to New Mexico and its bomb project. In the first year the basics of Radar system requirements had been established. Now, systems would have to be engineered for all those different requirements. That necessity soon brought in others, includ- ing me, whom Associate Director Loomis characterized with disdain as we don’t hire people who just walk in off the street! But necessity does change minds and training in Electrical Engineering (EE), not nuclear, was what was needed. I worked (or should I say served) in the Indicator Section from February 1942 till war’s end. Indicators were radar’s better to see you, enemy displays and the controls behind them. Major radar applications were soon put under subsection managers. I, in particular, pretty much stayed a lone hand at advanced component, circuit and some special systems development. Among my chores was an occasional high voltage (HV) problem. One, in particular, was a proposed audio oscillator circuit which couldn’t be made to work so was handed to me and cleaned up. Thus, almost by default, HV supplies became one of my responsibilities. Ancient Electronics and Modern Efficient Lighting Clayton A. Washburn Followers of the Antiques Road Show know that some artifacts of the 1950’s and 60’s are now antiques and greatly prized. Thus it can be surmised that the brand new electronics of World War II (WWII) and the weaponry it spawned are now antiques. advent of solid state, LCC held intriguing promise to replace incandescent lighting with a CRT-type bulb. Post-war, I made L-charge HV supplies for lab work at the Rauland Corp.. Their main product was the CRT. Detection of screen blemishes before final assembly with their flickering source of illumination was mar- AirborneRadar, besides likingminiaturization, had the pesky problem of HV insulation at high altitude. The smaller size of the com- ponents at audio frequencies made both smaller components and full encapsulation practical. That solvedbothproblems. Among other developmentswasone, however, which was too late for war work. It employed a ba- sic new concept which I dubbed L-charge. Formally it will be the inductance (L) Charge Converter circuit, (LCC). To some it will now be familiar as the earliest configuration of the now ubiquitous switch mode power converter. In 1944 a transformer was the one means to convert AC voltage levels. LCC provided a new concept for effi- cient conversion, ACor DC. It held promise for improvedperformance in many applications. Following, next page, is the circuit diagram and its brief descrip- tion taken from Vol. 22 of the MIT R L series. Due to limitations of the vacuum tube, prin- cipal applicationwould be for CRT and similar HV power supplies. Of others that I could envi- sion, it should provide themeans toDCpower transmission. That last was then considered the future of HV power transmission and surely L-charge would help speed it along. At the