No sooner had the transistor been invented, with its major advantage of reduction of circuit size, than people were thinking about simplifying circuit design and construction by using packaged circuits of various kinds. In November 1952, the Proceedings of the IRE published an article by J.A.Morton entitled "Present Status of Transistor Development" which describes a study of the "feasibility of applying transistors in the form of miniature packaged circuit functions". Seven package types were developed, each comprising a circuit card embedded in transparent plastic, with a tube/valve base at one end serving as a plug connector. They employed very early Bell Labs transistor types such as the M1752. The image on the right, taken from the article, shows two examples. The packages had different basic functions, and were connected together in different ways to build larger circuit blocks such as a binary counter and a shift register. The article suggests some improvements that would be needed to make the packages suitable for commercial use, but this technique does not seem to have been pursued further.
A gap of approximately ten years was to pass before encapsulated circuits were tried again. This time, it was Philips in the Netherlands who developed the "Series 1 Circuit Blocks", one of which is shown on the left with its original plastic holder, and on the right four are shown on a contemporary circuit card marked "100 KC DECADE". Since a decade counter requires four flip-flops, it is reasonable to guess that each red Circuit Block contains one flip-flop. There were quite a number of different types of these blocks, in many different bright colours, but all with the same ten wires emerging from one long edge. The block was made by fitting a small circuit board into a plastic case that was then filled with epoxy. It is hard to open them without destroying the contents, but I have opened one, and it contained three unbranded OC47 transistors and a few resistors. OC47 was a general purpose RF germanium PNP transistor made by Philips for internal and OEM use.
At about the same time as Philips were making the Series 1 Circuit Blocks, their UK manufacturing arm, Mullard Ltd, were selling a similar technology called "NOR Bricks", shown in the image on the right, approximately life size. These were black plastic cuboids with two rows of pins, eight on one side and nine on the other. In appearance they resembled huge DIL chips, except for the different pin count on each side. I don't know much about the technology used inside these.
All these circuit packaging technologies were commercial failures, but they are of historic interest. If you know anything about them, or have examples of them, or other obsolete techniques of circuit integration, please
No sooner had the transistor been invented, with its major advantage of reduction of circuit size, than people were thinking about simplifying circuit design and construction by using packaged circuits of various kinds. In November 1952, the Proceedings of the IRE published an article by J.A.Morton entitled "Present Status of Transistor Development" which describes a study of the "feasibility of applying transistors in the form of miniature packaged circuit functions". Seven package types were developed, each comprising a circuit card embedded in transparent plastic, with a tube/valve base at one end serving as a plug connector. They employed very early Bell Labs transistor types such as the M1752. The image on the right, taken from the article, shows two examples. The packages had different basic functions, and were connected together in different ways to build larger circuit blocks such as a binary counter and a shift register. The article suggests some improvements that would be needed to make the packages suitable for commercial use, but this technique does not seem to have been pursued further.
A gap of approximately ten years was to pass before encapsulated circuits were tried again. This time, it was Philips in the Netherlands who developed the "Series 1 Circuit Blocks", one of which is shown on the left with its original plastic holder, and on the right four are shown on a contemporary circuit card marked "100 KC DECADE". Since a decade counter requires four flip-flops, it is reasonable to guess that each red Circuit Block contains one flip-flop. There were quite a number of different types of these blocks, in many different bright colours, but all with the same ten wires emerging from one long edge. The block was made by fitting a small circuit board into a plastic case that was then filled with epoxy. It is hard to open them without destroying the contents, but I have opened one, and it contained three unbranded OC47 transistors and a few resistors. OC47 was a general purpose RF germanium PNP transistor made by Philips for internal and OEM use.
At about the same time as Philips were making the Series 1 Circuit Blocks, their UK manufacturing arm, Mullard Ltd, were selling a similar technology called "NOR Bricks", shown in the image on the right, approximately life size. These were black plastic cuboids with two rows of pins, eight on one side and nine on the other. In appearance they resembled huge DIL chips, except for the different pin count on each side. I don't know much about the technology used inside these.