Western Electric F-51618 & F-51619  
Written by Accutron on 2017-12-22  

Devices included in this entry:

Western Electric F-51618 NPN germanium alloy junction transistor
Western Electric F-51619 PNP germanium alloy junction transistor (pictured in thumbnail)


The Western Electric F-51618 & F-51619 are a complementary pair of germanium alloy junction transistors, developed in the late 1950s for the Bell #1 Electronic Switching System (1ESS). The F-51618 (BTL A-2037) is a NPN device, while the F-51619 (BTL A-2038) is a PNP device of similar construction. The F-51618 & F-51619 have the unique feature of dual redundant emitter and base internal leads.


Western Electric F-51618 NPN alloy junction transistor. This example lacks a printed part number, and may be a production prototype.


F-51618 transistor, underside construction. Despite the absence of a part number on this device, it can be easily identified by the green paint on the evacuation nipple. The F-51519 has red paint on its nipple.


Western Electric F-51619 PNP alloy junction transistor, manufactured in 1960. The F-51618 and F-51619 are rare examples of transistors with individual serial numbers.


F-51619 transistor, internal construction. The pedestal mounting arrangement allows for rapid heat dissipation.

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

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