Classroom Companion: Business

Box 2.1 The Transistor
The transistor is a semiconductor 
device used to switch and amplify elec-
tronic signals. It effectively replaced 
vacuum tube technology and enabled 
the production of cheap, low-power, 
and small electronic devices. It is the 
basis for almost all ICT devices such as 
microprocessors, personal computers, 
smartphones, and other electronic tools. 
It is the most important invention of 
 
Chapter 2 ·
Information and Communication Technologies

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19
2
the twentieth century, perhaps the most 
important invention of all times.
Julius Edgar Lilienfeld had already 
filed a patent for the field effect transis-
tor in 1925. However, because of the 
lack of high-quality semiconductor 
materials, it was impossible to build 
a working transistor at that time. The 
first practical implementation of the 
transistor was done at Bell Labs, USA, 
by John Bardeen, Walter Brattain, and 
William Shockley in 1947. What they 
invented was the first point- 
contact 
transistor which they patented the year 
after. They received the Nobel Prize in 
Physics in 1956 for their “research on 
semiconductors and their discovery of 
the transistor effect” (See 
7
https://
w w w. n o b e l p r i z e. o rg / p r i z e s / p hy s -
ics/1956/summary/
).
The transistor radio was the first 
commercial device designed using tran-
sistors (1954). In its early days, the 
transistor also found its use in pocket 
calculators, hearing aids, telecommuni-
cation switching equipment, and then, 
finally, the personal computer and the 
mobile phone. Today, transistors are 
mostly used as building blocks for inte-
grated circuits which, in turn, are used 
to produce personal computers, smart-
phones, and other electronic devices. In 
2014, more than 10
18
transistors were 
produced. This is more than 100 mil-
lion transistors for each human being 
on Earth. From 1960 to 2018, altogether 
1.3 × 10
22
transistors have been manu-
factured (Laws, 
2018
).
The size of a single transistor has 
continually gotten smaller since its 
inception in the 1950s, quite accurately 
following Moore’s law. While the Intel 
4004 microprocessor released in 1971 
had 2300 transistors, each with a size 
of 10,000 nanometers, the 22-core Xeon 
Broadwell-E5 microprocessor released 
by Intel in 2016 has 7,200,000,000 tran-
sistors each with a size of 14 nanome-
ters (Wikipedia, 
2020
). More transistors 
mean in general more computing power. 
Whether or not the size of transistors 
can be further reduced in the future 
according to Moore’s law is an open 
issue. In the end, quantum effects, heat-
ing, and thermal noise may limit the 
minimum size of a transistor.