When is a valve not a valve? When it’s a tube…..

Recent conversations with our customers have demonstrated that some confusion exists about what differentiates a “valve” from a “tube”. The Essex Amp Repairs team will now attempt to shed light on things… The terms “valve” and “tube” have their origins in the earliest days of electronics. When the use of thermionic triode devices began to gather favour, two types of terminology became commonly used. In Great Britain, the description of the function of the thermionic triode was analogous to a valve controlling the flow of liquid. And so, in the UK, the term “thermionic valve”, later shortened to “valve” became commonplace. In the United States, the device was described more in terms of its physical construction. As the electronic components within the device are contained in an evacuated envelope or “tube”, the term “vacuum tube” (later shortened to “tube”) became commonplace. From this, it can be seen that valves and tubes are the same thing. The terms of reference can be used interchangeably. A good example of two great nations being separated by a common language.