Learning material for understanding how a varactor diode works

Thread Starter

dan404

Joined Jan 2, 2021
1
Hi, i am intrested in understanding how a varactor diode works. Do i need a semiconductor physics book? Are there books sepecialized on varactor diode wokings? Please reference useful books on varactor diode workings or whatever topic i need. I already know analog electronics, circuits and electromagnetism.
Thanks!
 

Delta Prime

Joined Nov 15, 2019
1,147
Hello there :) A varactor diode is a simple variable capacitor that allows oscillator circuits and other circuits to be easily tuned by applying a voltage. These diodes have a similar structure as a p-n diode; the structure of a varactor diode is rather simple and illustrates its power as a component with nonlinear reactance . But then again you already know this cuz you're well schooled in analog!
Please forgive me I get cranky around dinner time if I didn't have lunch. ARRL.http://www.arrl.org/
Everything you ever wanted to know about varactor diodes. :)
 
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crutschow

Joined Mar 14, 2008
27,696
All junction diodes show a variation in junction capacitance with reverse bias.
Varactor diodes have their junction doped to increase this characteristic to the maximum possible.
 

RCory

Joined Sep 10, 2012
1
Hi, i am intrested in understanding how a varactor diode works. Do i need a semiconductor physics book? Are there books sepecialized on varactor diode wokings? Please reference useful books on varactor diode workings or whatever topic i need. I already know analog electronics, circuits and electromagnetism.
Thanks!
I wrote an article on varactor diodes published in High Frequency Design magazine several years ago when I was the applications engineering manager of a microwave semiconductor company. I hope it helps.
 

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Gabby_Jay

Joined Aug 29, 2021
1
Is there a way to check a varactor diode when it's in a circuit similar to the way a silicon diode can be checked with the diode checking function of an ohmmeter?
 

Delta Prime

Joined Nov 15, 2019
1,147
Hello there!
You should have already answered your own question,if you just take a moment and read any of the suggestions that have been given to you. I mean this in the best possible way! :) In circuit testing with a digital multimeter or VOM the answer is no.
Now with that said! I myself troubleshooting RF systems have used an RF service monitor and a digital multimeter to troubleshoot to the component level and I have found defective Varactor diodes in circuit but you see... I know what I'm looking for.If this is an oscillator circuit using varactor diodes you can measure the frequency drift with respect to time, as well as the phase noise with what is called a spectrum analyzer.
 
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