TRANSISTOR MUSEUM  

Historic Transistor Photo Gallery   

 

 

 

 

Transistor Size (1/2”L X 3/8”W X 1/2”H)

Date Code 5-47 (1955 Week 47) on Back

 

 

Plastic Tube

Some Plastic Tubes Have No Markings

 

 

GE 2N78

 

TYPE

Germanium NPN Grown Junction

Hi Frequency

 

USAGE

Industrial/Mobile 

 

DATE INTRODUCED

1955

 

CASE STYLES

Black Metal Oval Pinched Top (Early)

Black Metal Top Hat (Later)

 

AVAILABILITY

Common (High Volume Production)

 

HISTORIC NOTES

Although General Electric was known for leading in the development of alloy junction germanium transistors, this pioneering company also developed grown junction devices, building on a leadership position in germanium diode technology. The 2N78 was a very successful early germanium high frequency type, using a unique “rate-grown” process developed by GE, which used grading doping of the base region to achieve reasonable performance at frequencies up to 6 MHz.  Lafayette Radio offered the 2N78 for $5.25 in 1955, and the price remained relatively high for several years ($3.75 in 1960), indicating a good market for this early high performer. As with all metal-cased GE transistors, most existing units exhibit only minor performance degradation, even after 50 years.  The 2N78 continued to be manufactured through the mid 1960s.

 

 

 

 

 

Copyright © 2004 by Jack Ward

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