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During the 20th Century, Vacuum Tubes Improved in a Moore’s Law-Like Way

Their improvement had to do with power density rather than miniaturization

3 min read
Progression of power density for major device types
Source: V.L. Granatstein, R.K. Parker, and C.M. Armstrong, Proceedings of the IEEE, Vol. 87, No. 5, May 1999

In the 48 years since the introduction of the first microprocessor, in 1971, the number of electronic components that can be crammed onto a given area on a chip has increased seven orders of magnitude. That corresponds to a doubling about every two years [see “Moore’s Curse,” IEEE Spectrum, April 2015].

You might think that the performance of previous vacuum-tube electronics could not possibly compare with that record of improvement. Not so. It’s just that the key metric of improvement is different.

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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