What Are Electron Tubes?

An electron tube, vacuum tube, valve (Britain), or tube (North America) is a device that is capable of managing the flow of electric current in a high vacuum. Before the advent of semiconductor technology, electron tube parts were present in countless electronic circuits through the first half the 20th century. While they originally served numerous applications such as early televisions and digital computers, they can still be found in a number of military and aviation assemblies to this day due to their consistent advancements and unique capabilities.

A typical electron tube assembly consists of a sealed glass or metal-ceramic enclosure that contains two or more electrodes. The electrode parts are secured to leads that pass through the airtight seal of the assembly and attach to pins which are then plugged into a tube socket. Electrodes come in a few forms, those of which are the cathode, anode, and grids. The cathode is the electrode that is heated by a filament, and the increase in heat causes the cathode to begin emitting electrons. With the anode, electrons emitted from the cathode are attracted.
For most modern electron tube assembly types, heating is provided to the cathode indirectly. As such, the filament is not attached to the cathode itself for heating. While direct attachment ensures that heating is sufficient for the release of electrons, such assemblies often limit the flexibility of such components. With indirect heating, however, the cathode can have a higher potential during operation or may be run in parallel.
The grids of the assembly are electrodes that feature variable potential, and such valve parts serve to manage the flow of electrons between the anode and cathode. The control grid is a part that is implemented for the means of managing electron flow, and it limits the amount of electrons moving from the cathode to the anode through the use of negative voltage. The screen grid is another part that operates at a fixed positive potential that is lower than the anode. As it is decoupled with a capacitor and serves as a screen between the anode and control grid, performance is often high. The suppressor grid is attached directly to the cathode, and it is typically kept at a low voltage. With such grid parts, a lower voltage region is produced between the anode and screen grid in order to achieve a high amplification factor for the tube or valve.
Despite being superseded by semiconductor technology for many applications, electron tube parts may still be found in certain aircraft and military equipment due to their ability to better resist transient overvoltages which can be crucial for such industries. At ASAP AOG, we operate as a premier online purchasing platform for aircraft, NSN, and electronic parts, and we are your sourcing solution for top quality electron tubes that accommodate numerous applications. If you would like to begin the purchasing process, start with a competitive quote for your comparisons through the submission of an RFQ form. Our services are available for customers 24/7x365, and you may reach our representatives by emailing us at sales@asapaog.com or calling us at 1-714-705-4780.


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