1951 · Production Point-Contact Transistor · Work 819 of 1,871
Small transistor cartridges of 1951 on a pale workbench in a telephone equipment factory in Pennsylvania, each a metal cup eleven millimetres across and thirteen millimetres high with a pale paper band and two bent wires at its top, a woman's hand in a light blue smock sleeve holding one in a small holder while a fine needle enters a tiny hole in its side wall, beside it a wooden tray with rows of identical cartridges standing in drilled holes, a magnifier lamp on a jointed arm, fluorescent tubes as bright stripes on the ceiling soft in focus, the edge of a conveyor belt, factory windows.
What it was used for
According to Transistor Museum documents the Type A point-contact transistor was made in small numbers at Bell Labs in Murray Hill between 1949 and 1951, over 3,700 units by mid-1949, and, according to Industrial Alchemy, went to other companies for testing. Each unit was hand serialised and its operating parameters were printed on the packaging. On 1 October 1951 Western Electric started a transistor production line at its Allentown works in Pennsylvania. In May 1952, per Radio-Electronics, nearly 8,500 transistors were produced monthly in the United States; Western Electric made 6,000 of them, Raytheon 1,000, General Electric 800, RCA 400. The same article gives military procurement as 6,000 per month and a mail-order catalogue price of $18 each.
What was new
The metal cartridge case made the Type A, in the Transistor Museum's words, the first mechanically rugged point-contact transistor: a cartridge instead of a laboratory assembly. A side window closed with a plastic tube allowed the contact points to be readjusted by hand; the original form had leads so thick and so sharply bent that socket mounting was impossible. That Allentown was the world's first transistor manufacture is not settled: the Computer History Museum states that thousands of "transistrons" were already being made in Paris at the Compagnie des Freins et Signaux by mid-1949 for the French telephone network. When the more robust grown-junction transistor reached the market in 1952, the device was rendered obsolete, and apart from early hearing aids and a few switching systems it saw almost no use, according to Industrial Alchemy.
What the sources leave open: The IEEE plaque at Allentown says only "The commercial manufacture of transistors began here in October 1951" and takes no position on the Paris production; neither source says whether this is a contradiction or a matter of definition. Reject rates on the Allentown line, and the often-cited use in the card translator of Bell's toll dialling system, are not documented.
Connections
Every connection names its kind. “Forerunner” on its own would be a claim.