The rise of designators:
from DeForest to Western Electric
By David Ray Cyber City Circuits
The before times There once was a time before the age governed by part numbers and catalogs. The industry was young, and everything was chaos. Before the late 1920s, vacuum tubes were primarily used for R&D, purpose- built, and made in low volume. Consumer A.M. radios did exist at the time, but the variety of tubes available to consumers was so small that each could have its own model name or arbitrary identifier. As quickly as a small vacuum tube and radio manufacturer sprung up, they were bought up by the competition, and everyone wanted to be unique and difficult in their way.
Each manufacturer would use their own sizes, form factors, pinouts, and part numbers. As a radio service person, you had to always keep a dozen different vacuum tube databooks with you, just so that you could find substitutions and that’s only if you were lucky. Then, could you believe it, multiple manufacturers would use the same part number for two completely different parts? After World War 2, many of the small brands had been swallowed up by the behemoths of their day, which made repairing and maintaining the existing equipment even harder. There needed to be
some sort of ‘registered standard’ for parts. Today, every tiny part inside of your favorite electronic devices has a part number. How did we get here?
This is the story of the naming convention used in the EIA RS-370: Designation System for Discrete Semiconductor Devices.
we get technical
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