Difference between Diode and Triode

Difference between Diode and Triode

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An electric circuit consist of three components Transistors, Diode and Triode. Each have different parts and have own functions. Diode and Triode majorly comprises of Vacuum tubes because they wont allow other inert gases to interfere the functionality. Lets see briefly about the Diode and Triode below.


The term duo means two. The term itself defines diode is a two Terminal electronic component which has two basic major functions, that are primarily conducting current in one direction and have high resistance in the other.

It was designed by J. A Fleming in 1904, diode valve consists of two electrodes placed inside an evacuated glass envelope. One electrode is called cathode which is made up of tungsten on which there is a thin layer of Barium oxide. When heated cathode emits electrons. This electron flows towards the other electrode called anode or plate. Which is at positive potential and as a result an electric current is distributed in the circuit. The electrons emitted from the cathode are collected in the evaluated space around it. This collection of electrons is called space charge which is obviously negative. Diode valve act as a rectifier. Rectifier is a device which converts alternating voltage into direct voltage.


As like diode triode means three. The Triode is an electronic amplifier vaccum tube consisting of three electrodes inside an evacuated glass envelope. The three electrons inside a evacuated glass envelope are heated filament or cathode, a grid and plate also called as anode.

The Triode valve is designed by Lee De Forest in 1907, triode valve is a modified form of usual diode and it consists of a usual anode, cathode pair and one more electrode called control grid. Triode valve can be used as a amplifier, oscillator,  transmitter and a detector.

Difference between Diode and Triode

Difference between diode and Triode:

Diode Triode
No. Of Terminals
Diode is a 2 Terminal component. Triode is a 3 Terminal component.
The basic function of the diode is primarily conducting current in one direction and having resistance in the other. Triode is an electronic amplifier vacuum tube
It consists of two electrodes. It consists of three electrodes.
it consists of rectifier which alternates voltage into direct voltage It doesn't have a rectifier
Diode is mostly used in turning AC into DC, mixing signals etc., Triode is mostly used as amplifier, oscillator and detector.


The main difference between Diode and Triode is that the diode is an electronic component with two terminals that allows current to flow in one direction and Triode is a single grid amplifying vacuum tube having three active electrodes.

If you want to read more about Difference between Conductors and Insulators click here.

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