TRANSISTOR MUSEUM™  

Historic Transistor Photo Gallery   

 

Diode Size 1N51 (1/4” Diameter X 3/8” L)

Date Code on Back 329 (1953 Week 29)

Diode Size 1N107/8 (1/8” Diameter X 3/8” L)

No Date Code

3 3/8” X 1 9/16” Cardboard Package Labeling

See Page 2 for More NU Diode Photos

 

NATIONAL UNION

GERMANIUM DIODES

1N51, 1N107, 1N108

 

TYPE

Germanium Point Contact Diode (1N51) and Gold Bonded Diodes (1N107, 1N108)

 

USAGE

General Purpose, Commercial Radio/TV

 

DATE INTRODUCED

1952/53

 

CASE STYLES

Green Epoxy

 

AVAILABILITY

Rare (Limited Production)

HISTORIC NOTES

In the early 1950s, National Union Radio Corp was manufacturing germanium diodes and transistors in limited quantities.  The diodes were of two general types: point contact and gold bonded.  Both types were suited for various general purpose and commercial radio/TV receiver applications.  This was a very challenging business, with much larger and more successful competitors such as Sylvania and Raytheon.  National Union remained in the semiconductor business for only a few years in the mid 1950s.  Shown above are samples of both types of NU diodes.  The 1N51 was marketed as a general purpose diode, similar to the very popular 1N34A type pioneered by Sylvania.  The 1N107/8 represent gold bonded types, which were valued in radio/TV circuitry because of better performance characteristics than the older point contact type.  Due to the early and brief period of manufacture, and the scarcity of documentation and remaining devices, National Union semiconductor diodes are quite historic.   NU devices are notable and easily recognizable because all known samples were manufactured using differing shades of green coloring in an epoxy body.     

Copyright © 2007 by Jack Ward.  All Rights Reserved.

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