Historic Transistor Photo Gallery

Photo Essay – Bell Labs Type A







     Type A Transistor Courtesy Terry Hosking






         Cutaway View of Type A Transistor


Photo Essay Commentary

A very unique aspect of the Type A transistor is the unusual mechanical placement of the two leads (collector and emitter) which emerge from the bottom of the case.  As shown in the photos above, the two leads are bent at an approximate 90 degree angle to the vertical plane of the cartridge.  In addition, the collector lead, when viewed from the bottom, is offset 20 degrees from the straight line formed with the emitter.   This distinctive mechanical layout provides an unambiguous method for identifying Type A transistors, since this lead placement approach was abandoned early in transistor development at Bell Labs, and appears to have been ill suited for commercial production.  Becker and Shive [2] indicate that the Type A transistor had been originally developed by W.G. Pfann, and that R.J. Kircher modified this design to accommodate a socketing scheme.  The overall construction of the Type A is shown in a cutaway view above.


Go To PhotoGallery Type A Page 3






Copyright © 2004 by Jack Ward. All Rights Reserved.