Western Electric 20D  
Written by Accutron on 2017-02-09  

The Western Electric 20D is a diffused junction silicon NPN power transistor rated at 1.5W. The 20D was widely employed in Bell System telephone equipment, and uses the same TO-38 canister construction as the 2N1072.

Western Electric 20D silicon NPN power transistor.

20D transistor, underside construction.

20D transistor, internal construction.

This article is part of the [Discrete Semiconductors] exhibit.

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