a website collaboration between Science Service and the Smithsonian Institution

1960 - universal circuit card will conform any desired circuit function


CD 2478083 E&MP15.002

Electric Circuits, Breakers

June 16, 1960

Development of a "universal" circuit card which can be prefabricated and adapted to different circuit requirements has been announced here today by Librascope, Incorporated, 808 Western Avenue.

The stock card developed by Librascope engineers contains a universal etched pattern which can be modified by interconnections to form any desired circuit function, according to Lewis W. Imm, president of the firm.

The computer field has long believed that the standardization and prefabrication of components and subassemblies which can be used in more than one special model of a computer is an impossible concept. Librascope's approach to the problem was to make careful and analytical consideration of the basic design parameters of each class of computer to determine the general circuitry needed.

On the stock cards developed from this study, components may be added to form logic modules before the final design of the computer is ready, and then, when the design is firmed, these modules may be interconnected to form the required circuits.

Such a technique is particularly adaptable to short run and prototype production, where lead time between design and actual start of production is usually excessive.

A good example of the use of this new technique is in the prefabrication of the four huge data processing central computers Librascope recently completed for the Federal Aviation Agency’s air traffic control program. Each computer card is capable of taking 33 individual modules, and interconnection was made after the final computer design has been firmed.

Librascope is a leading manufacturer of special and general purpose computers for military and commercial markets. The company designed and produces the desk-sized LGP-30 general purpose digital computer, which is in operation throughout the world. Librascope, a subsidiary of General Precision Equipment Corporation, also manufactures recording instrumentation and electro-optical systems.

In producing the universal printed circuit cards for the various types of computers built at the Glendale plant, assembly is divided into two steps. The first part is pre-assembly, at which point all cards destined for a specific class of computer look alike. This preassembly stage takes place before the logical design of the computer has been completely firmed by the engineering department. This permits the industrial engineering department to perform a large amount of fabrication prior to the start of full production.

The second phase of production involves working out the interconnections of the individual modules to provide the proper circuits for the computer. This is done after the computer design has been completed.

The technique was developed to speed production of extremely short run equipment, and does not result in the most compact packaging, or in a card that is particularly adaptable to mass production., according to Mr. Imm. But where a single unit or less than five machines are being built, savings in production time and reduction in the lag between design and assembly makes this technique highly desirable, he pointed out.

Another innovation in the special Librascope card is that the etched circuitry is carried through from the base plug of each card to the top of the card where a duplicate connector is provided. This permits the card to be connected to a test instrument while it is plugged into the computer.

In order to facilitate checking, circuitry used in a computer such as an FAA data processing central restores signals at each gating point throughout the machine to eliminate signal degeneration. Since all connections are available at the top of the cards, an auxiliary maintenance panel can be plugged in and troubles can be diagnosed without the necessity for circuit crawling with an oscilloscope. This materially reduces testing and checkout time during final inspection.

The technique developed by the California company result in both cost and lead time reduction for the customer, Mr. Imm pointed out. 

Original Caption by Science Service
©Librascope, Incorporated

Kearfott (logo)
LINK (logo)

National Museum of American History


Search - Site Map - Subjects to Choose From - Numbering Format

Credits - Copyright - Comments