Computer History

History of the Transistor and the Transistor Computer

The invention of transistors is one of the most important breakthroughs of the 20th century. In fact, most electronic devices used in day-to-day activities rely on transistors. From the simple calculator to complex alarm systems, this minute electronic component has made major contributions in electronics and electronic communications.

The Dawn of Transistors

Transistors are semiconductor devices that have two main functions in an electronic circuit – an amplifier and a switch. Before the era of transistors, vacuum tubes were predominantly used as an amplifier or a switch for the first half of the twentieth century. However, the high operating voltage requirement, high power consumption, and high production of heat caused vacuum tubes to become inefficient and unreliable over time. Not to mention, these tubes are bulky and fragile because the casing is made of glass. To solve this dilemma, years of research were done by different manufacturers for a suitable replacement.

At long last, in December of 1947, three physicists from Bell Laboratories successfully invented the first working transistor. John Bardeen, Walter Brattain, and William Shockley spent years of research to finally develop a working point-contact transistor. Shockley further improved the device into a bipolar junction transistor in 1948, which was the type of transistor that was widely used in the 1950s. Such was the importance of their invention that Bardeen, Brattain, and Shockley were awarded the renowned Nobel Prize in 1956.

Evolution of Transistors

Much like any other device, transistors have also gone through several innovations. Back in the late 1950s, germanium played a crucial role in the development of transistors. Germanium-based transistors, however, have major drawbacks, with current leakage and intolerance of temperatures greater than 75 °C. Additionally, germanium is rare and expensive. This prompted the researchers at Bell Labs to look for a better alternative.

Gordon Teal a resounding name in the evolution of transistors. An American engineer at Bell Labs, Teal developed a method to produce pure germanium crystals to be used for germanium-based transistors. Likewise, Teal experimented with silicon as a possible replacement for germanium. In 1953, he moved back to Texas after he was offered the research director position at Texas Instruments (TI).[1] Bringing his experience and knowledge on semiconductor crystals, he continued to work on purified silicon as a replacement for germanium. In April 1954, Teal and his team at TI developed the first silicon transistor, which was announced to the world in May of that year. Because of its superior characteristics, silicon gradually replaced germanium as the semiconductor used for transistors.

With the introduction of silicon transistors, researchers at Bell Labs achieved yet another breakthrough by developing a transistor that could surpass the performance of the bipolar junction transistor. In 1959, Mohamed Atalla and Dawon Kahng invented the metal-oxide-semiconductor field-effect transistor (MOSFET) with lower power consumption and higher density than the bipolar transistor. These valuable characteristics greatly popularized the MOSFET transistor, which has since become the most widely manufactured device in history.[2]

Transforming Computer Technology

The invention of transistors was also revolutionary in the miniaturization of computers. Like earlier electronic devices, the first generation of computers used vacuum tubes as switches and amplifiers. After the advent of transistors, manufacturers also adopted the small device to build smaller, more efficient computers. In the years that followed, vacuum tubes were completely replaced by transistors, giving rise to the second generation of transistor computers.

The first computer to use transistors was believed to be the University of Manchester Transistor Computer. The Transistor Computer was built as a prototype, consisting of 92-point contact transistors and 550 diodes, and became fully operational in 1953. In 1955, the full-sized version of this computer was introduced, with 200-point contact transistors and 1300 diodes. Though the majority of the circuit used transistors, this device was not considered a completely transistorized computer, as vacuum tubes were still used in its clock generator.[3]

In the mid-1950s, similar machines began sprouting up. The University of Manchester’s design was later adopted by Metropolitan-Vickers, who produced seven machines using bipolar junction transistors in 1956. However, the device, called the Metrovick 950, was not commercially available and was only used within the company. Likewise, Bell Labs came up with the TRADIC device in 1954,[4] but like the Transistor Computer, the TRADIC used vacuum tubes for its clock power.

Built for the US Air Force in 1955, the Burroughs Atlas Mod 1-J1 Guidance Computer was the first computer to eliminate vacuum tubes entirely, and this model was the first fully transistorized computer. MIT also developed TX-0, their own transistor computer in 1956. Transistor computers also began to emerge in other parts of the world. The first device to show up in Asia was Japan’s ETL Mark III, released in 1956. The DRTE, released in 1957, and the Austrian Mailüfterl, released in 1958, were Canada’s and Europe’s first transistor computers, respectively. In 1959, Italy also released their first transistor computer, the Olivetti Elea 9003, which was later made available in the private market.[5]

Although transistor computers were emerging globally in the 1950s, they were not made commercially available until 1959, when General Electric released the General Electric 210. Consequently, other manufacturers also introduced their own flagship transistor computer models. The IBM 7070 and the RCA 501 were some of the first models released, among others.[6] Large-scale computers also followed this trend. The Philco Transac models S-1000 and S-2000 were among the first commercially available large-scale transistorized computers.

The evolution of transistor designs brought about major changes in computer design. The production of transistorized computers increased over time, as the technology became available commercially. Eventually, integrated circuits were adopted in the 1960s, giving way to the third generation of computers.

Small Size, Big Changes

Transistors have been preeminent since their invention over 70 years ago. This technology has propelled the invention and development of many other electronic devices. The humble size of the transistor does not cloak the magnitude of its contribution to technology. The transistor has undeniably changed the face of electronic circuitry and has brought about significant changes in the world, particularly in computer technology.

About the author

Glynis Navarrete

A freelance blogger who loves to write about anything related to technology. Born and raised in the Philippines and worked in Singapore for eight years as Technical Support for a wide range of IT equipment. Took a dive into the world of freelancing and now enjoying doing what I’m passionate about while not losing touch with technology.