Basic knowledge of vacuum tubes

Vacuum Tube Fundamentals

What is vacuum tube and its uses? 

In electronics, a vacuum tube, an electron tube, or valve, or colloquially, a tube, is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The simplest vacuum tube, the diode, invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode.

The basic working principle of a vacuum tube is a phenomenon called thermionic emission. It works like this: you heat up a metal, and the thermal energy knocks some electrons loose. ... When the cathode is heated, and a positive voltage is applied to the anode, electrons can flow from the cathode to the anode.

From this page, you can know the complete vacuum tube basics.

Vacuum Tube Types

What are the types of vacuum tubes?

There are a lot of different vacuum tube types, all with their own applications, characteristics and construction, most of which fall into four general types: (1) The diode, (2) the triode, (3) the tetrode, and (4) the pentode. This page lists the different vacuum tube types.

Different Types Of Vacuum Tubes
↪️Diode Vacuum Tubes
One of the simplest forms of vacuum tubes is the diode.
↪️Triode Vacuum Tubes
With this type of vacuum tube, the electric currents flow from the V+ having a high potential that has been applied on the anode end to the cathode’s ground potential.
↪️Tetrode Vacuum Tubes
The main idea behind the creation of the triode is related to the formation of the tetrode. It consists of a fourth electrode known as the screen located between the grid and the anode.
↪️Pentode Vacuum Tubes
This kind of tubes is directly connected to its cathode, using a connection inside the vacuum tube or with an open connection between the matching pins.

Vacuum Tube Applications

What are uses of vacuum tubes?

Vacuum tube is used as a switch, amplifier or display screen (CRT). Used as on/off switches, vacuum tubes allowed the first computers to perform digital computations. From here we can know vacuum tube or thermionic valve technology that provid the first form of active device used within electronics and they are still used in some specialist applications. For example, this simple device had tremendous implications for sound reproduction, which makes possible the next advancements in sound technology.