difference between Photodiode , Varacter diode , Tunnel diode

amelia's picture

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Joined: Sep 25, 2018

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difference between Photodiode , Varacter diode , Tunnel diode
August 19, 2019 - 12:12pm

i need help  understanding how these diodes work and what is their function ?

1.Photodiode 2.Varacter diode 3.Tunnel diode

Ferry's picture

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Joined: Sep 20, 2018

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difference between Photodiode , Varacter diode , Tunnel diode
August 19, 2019 - 5:46pm

A photodiode is similar to battery that produces current in the forward directions when light shines on the photodiode.

A varacter diose is similar to capacitor/condenser whose capacitance changes with reverse voltage across it. A varacter diode is used to adjust a tuned circuit resonant frequency by changing the DC voltage across diode. 

A tunnel diode is similar to an ordinary diode where except that it has a -Ve resistance over part  of the VI forward characteristics.

These are the differences between three of them/ each has its unique applications and can be used within one circuit board or within multiple.