Electron tubes, also known as vacuum tubes, are devices that are made of either glass tubes or metal enclosures, which functions by controlling the flow of electric current. They contain electrodes that are helpful in amplifying alternating currents and electric oscillations.
Alternatively called valves, electron tubes were actually used as an amplifier or switch for earlier computers, but they’ve been around for years. These components also help build radio amplifiers, televisions, and other electronic products.
Over the years, though, more and more manufacturers have been using semiconductor materials in making integrated circuits and amplifiers. The electron tubes have been pushed to the background, even if high stability and low-noise vacuum tubes are still being used for high fidelity audio equipment.
Ambrose Fleming is recognized for developing the first electron/vacuum tube using the Edison Effect, which refers to the thermionic current that’s found in incandescent bulbs.
Electron Tubes Electrodes
There are four types of electrodes found in an electron tube: anode, filament, cathode, and grid.
- An anode can draw electrons from cathodes.
- A filament provides heat to the cathode so that it can produce electrons. This is what an indirectly heated cathode is like – the filament does not connect to the cathode.
- Cathodes are the heated electrodes, the ones that release electrons.
- Grid helps manage the flow of electrons from cathode to anode.
Types of Electron Tubes
There are many types of electron or vacuum tubes, and they are categorized into slow wave devices and fast wave devices. The most popular slow wave electron tube device is the diode, which acts as a one-way valve for electric currents. It is an essential element for many electronic systems.
Other types of electron tubes are the triode, CRT or cathode ray tubes, pentode, tetrode, TWT or Travelling Wave Tube, FEL or Free Electron Laser, and Cyclotron Resonance Maser or Gyrotron.