TRANSISTOR MUSEUM™  

Historic Transistor Photo Gallery   

 

Diode Size (1/8” Diameter X 3/8” L)

Date Code on Yellow Unit 013 (1950 Week 13)

No Date Code on Red Unit

3” X 11/2” Cardboard Package Labeling

See Page 2 for More CK705 Diode Photos

 

RAYTHEON CK705 GERMANIUM

 CRYSTAL DIODE  

 

TYPE

Germanium Point Contact Diode

 

USAGE

General Purpose/1N34 Equivalent

 

DATE INTRODUCED

1949/1950

 

CASE STYLES

Yellow Epoxy (Early)

Red Epoxy (Later)

 

AVAILABILITY

Rare (Production Limited to 1950s)

HISTORIC NOTES

In 1948 Raytheon began the manufacture of germanium diodes for use in UHF tuners in television sets.  Large scale production followed in 1949 and increased to such an extent that by the end of 1950, close to 100,000 were being built every month. By 1952, Raytheon was the 2nd largest manufacturer of germanium diodes, and continued to be a leading germanium diode manufacturer throughout the 1950’s, with sales of $1.5 million in 1956 alone.  These first Raytheon germanium diodes, also known as Crystal Rectifiers, had rough epoxy cases that were not hermetically sealed, and the internal diode junctions would often show degraded performance through time due to moisture penetration.  By the mid 1950s, more robust, sealed cases were used.  The most popular 1950s Raytheon Crystal Diode was the CK705, shown above in a 1950 yellow epoxy case.  This device was intended for general purpose applications and competed directly against the famous Sylvania 1N34 diode.  The Raytheon CK705, yellow or red, is well remembered by many electronics hobbyists from the 1950s, when this strikingly colored device was used in that first homebuilt AM radio!        

 

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