science

TR-55

TR-55 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand TR-55 rather than just read about it. In short: The TR-55, released in 1955, was both Japan's and Sony's first commercially available transistor radio. The use of transistors allowed the device to be much smaller than earlier vacuum tube radios.

Key takeaways

TR-55 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect TR-55 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of TR-55 from memory before moving on to harder problems.

Reference excerpt

The TR-55, released in 1955, was both Japan's and Sony's first commercially available transistor radio. The use of transistors allowed the device to be much smaller than earlier vacuum tube radios.

History Akio Morita and Masaru Ibuka, then operating under the business name Tokyo Tsushin Kogyo, had been working on plans to introduce a transistor radio to the market since 1953. The first model, released in 1955, was called TR-52, but was pulled from the market before it had even been introduced after climbing summer temperatures made the front lattice section gradually peel away from the black cabinet, forcing the company to build a new model using a more durable material. When the TR-55 was released in Japan in August 1955, it was the first transistor radio marketed in that country. The TR-55 featured the Sony name, but the company did not officially change its name to Sony until January 1958. In the autumn of 1955, Morita met with a representative of the Bulova watch company in New York City. Bulova agreed to order 10,000 units on the condition they carry the Bulova name. Morita declined the deal. Sony later signed a deal with New York importer Adolph Gross to distribute an improved and slightly more compact model, and in March 1957, the Sony TR-63 transistor radio would become Sony's first product sold in the US. The TR-63 would not fit in existing shirt front pockets, so the company issued shirts with expanded pockets to salesmen so they could claim the product was "the world's first pocket sized transistor radio".

Technical specifications Powered by four AA batteries, the TR-55 used a superheterodyne circuit incorporating two AF stages and covered the medium wave broadcast band. The TR-55 used the following transistors:

(1) 2T51 (oscillator-mixer) (2) 2T52 (for IF) (1) 2T53 (AF driver) (1) 2T12 The TR-55's five transistors were designed in house by Sony, the technology having been licensed from Bell Labs. This made Sony the first company to produce commercial transistor radios from the ground up. American company Regency had launched their Regency TR-1 transistor radio earlier in 1954, but bought the transistors from Texas Instruments. Printed circuit boards were used, which was unusual for the time.

Physical specifications The speaker grille was made from punched aluminum, and its design was reportedly inspired by Lincoln Motor Company automobiles of the era. Although it was not as compact as originally intended, the relatively small size of the TR-55 was a novelty, and attracted the attention of Japanese consumers.

Height: 140 mm (5.5 in) Width: 89 mm (3.5 in) Thickness: 38 mm (1.5 in) Weight: 560 grams

Illustrations

Worked examples

Example 1 — a first encounter with TR-55

Start with the simplest possible case. Write down what TR-55 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to TR-55 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about TR-55 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of TR-55

In research: TR-55 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses TR-55 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: TR-55 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1955 in radio, History of radio, Models of radios, so understanding it makes those chapters shorter.
In everyday life: Look for TR-55 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study TR-55 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what TR-55 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain TR-55 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is TR-55 in simple terms?

The TR-55, released in 1955, was both Japan's and Sony's first commercially available transistor radio. The use of transistors allowed the device to be much smaller than earlier vacuum tube radios.

Why does TR-55 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study TR-55?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on TR-55.