TRANSISTOR MUSEUM™ Historic Transistor Photo Gallery
Diode Size (1/4” Diameter X 3/8” L) Date Code on Similar Units (1959) 3” X 1 1/2” X 3/8” Cardboard Box with Removable Lid See Page 2 for More 1N81 Diode Photos	CBS HYTRON 1N81 GERMANIUM  CRYSTAL DIODE   TYPE Germanium Point Contact Diode USAGE General Purpose/Military DATE INTRODUCED Early 1950s CASE STYLES Brown phenolic plastic AVAILABILITY Rare (Production Limited to 1950s)
HISTORIC NOTES By the late 1940s, the germanium crystal diode market was expanding into the hundreds of thousands of units annually, largely to support the growth of the TV receiver market.  Several large vacuum manufacturers became leaders in diode production, including Sylvania, General Electric and Raytheon.  Other smaller electronics companies entered this market, including CBS Hytron, a company formed when CBS purchased a small vacuum tube company (Hytron) in order to establish a presence in the semiconductor manufacturing field.  CBS was offering a complete range of germanium diodes (and transistors), beginning early in the 1950s.  Most of these products were based on device types and technologies created by larger, more research oriented companies.  For example, CBS was one of many companies to offer a “1N34” germanium diode, based on the universally popular device developed by Sylvania in the mid 1940s.  The 1N81 diode had been developed initially by General Electric in 1950, primarily to support the military need for a rugged, general purpose germanium diode.  CBS was one of several companies to provide second-sourcing for the 1N81, and introduced their version in 1952.  These are excellent general purpose diodes, rugged and reliable, and can be used in most circuits interchangeably with the 1N34.
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