Handling the Metric Prefixes
July 1962 Radio-Electronics

July 1962 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

Even for those of us who were around when the "old" numerical prefixes became common parlance, it is difficult to remember having ever used them. Although my introduction to terms using kilo, mega, milli, and micro was not until about a decade after this 1962 Radio-Electronics magazine article was published, I remember my electrical circuit instructor in high school using the micromicro type prefixes, and some of the capacitors and inductors were marked thusly. After nearly forgetting about the old designations, about 15 years ago I began buying and reading these vintage electronics magazines and suddenly was seeing them all over again. You might wonder why the newer prefixes representing high orders of magnitude (larger powers of ten) were not used sooner. The answer is that technology had not advanced far enough to facilitate frequencies above the hundreds of MHz and, reciprocally, components below hundredths of a μF or μH.

Handling the Metric Prefixes

By Rufus P. Turner

Whether we are concerned with large or small quantities, the metric prefixes save a lot of time, breath, and printer's ink. Most of these have been around a long time, and electronic men use a few of them very often (centi-, kilo-, mega-, micro-, and milli-).

We have gone on to compound them, to express the very large and the very small (thus, kilomegacycle, micromicro-watt, etc.) and the thing got out of hand a long time ago. Now we have four new prefixes which do away with such mouthfuls. Instead of 1 millimicro-second, we can now say 1 nanosecond; instead of 10 micromicrofarads, 10 picofarads; and instead of 2 kilomegacycles, 2 gigacycles.

The accompanying table will be convenient for converting metric quantities of one order of magnitude to those of another order. Simple multipliers are given. Thus, to convert microfarads into picofarads, multiply by 10⁶ (which is 1,000,000); to convert kilocycles into megacycles, multiply by 0.001; to convert nanoseconds into microseconds, multiply by 0.001. Clip this table and paste it in your notebook.