Transistors are current amplifiers. Their greatest limitation is that they are temperature-sensitive.

Test methods and specifications are necessary for the proper evaluation of transistors because they are temperature-sensitive devices whose characteristics and parameters vary over wide ranges.

Because individual transistors vary tremendously in their initial characteristics, a transistor checker is far more important to transistor circuitry than tube testers are to vacuum-tube circuits.

The experience gained in working with vacuum tubes does not always carry over into the realm of transistors. While transistor circuits can be designed and used based on the principle of analogy to vacuum tubes, yet transistors must be handled in their own way, must be wired, tested, protected and operated in a manner often at complete variance to vacuum-tube techniques. The four chapters that follow describe how to use the new methods and techniques that are required by transistors.

There has been, and still is, a tendency on the part of electronics technicians and engineers to make comparisons between vacuum tubes and transistors.

Similar circuit arrangements are used with both vacuum tube and transistor amplifiers. This similarity applies to the circuit arrangement only, however, and it is incorrect to consider the transistor as a direct substitute for the vacuum tube.

The electrical ratings of transistors are generally given in terms of a few basic characteristics. Since these characteristics are, for the most part, different from those used to describe vacuum tubes or other electronic components, it is important that the electronic technician, student, and serviceman become familiar with them.

Transistors, important as they may be, represent only a part of a large group of semiconductor devices. Year: 1953

As for the future of the transistor. . .one engineer has said - "Within a few years. . .five to
ten at the most. . . .we may expect to see more transistors than vacuum tubes used in new equip-
ment!" Year: 1953

Let's see the transistors practical application in electronics, radio and television. The development of a new vacuum tube, transformer or capacitor, important as it may to be to one branch of the field, generally has little over-all affect on the industry.