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Topic: building a digitally controlled variable capacitor (Read 1 time) previous topic - next topic

the digitally controlled variable capacitor  I was looking at getting is still listed on digikey, but is no longer manufactured. so, looking at the data sheet, it looks simple to build. the question i have, is what is the control circuit called? it has something to do with a single in controlling transistors that connect/disconnect about 5 capacitors. It is a simple circuit, and seems that there should be lots of option already designed and tested.

CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

http://www.intersil.com/content/dam/Intersil/documents/fn81/fn8156.pdf

CrossRoads

Looks like plenty available at Mouser
http://www.mouser.com/Search/Refine.aspx?Keyword=x90100
"New At Mouser" hardly seems to indicate discontinued.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

thank you. if i can get it, then it will be the easy way and i was looking forward to building a bulky circuit.

Runaway Pancake

7.5 - 14.5 pF

How about "Fun WIth Varactor Diodes"?
"Hello, I must be going..."
"You gotta fight -- for your right -- to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"
Hey - it's "bipolar transistor" or "junction transistor"; "BJT" is just stupid.

Paul__B

Perhaps you should remind us of what it is you propose to do with this digitally controlled variable capacitor.

If it is in regard to controlling the frequency of an oscillator as you have previously implied, then it is almost certainly an inappropriate approach as direct digital synthesis (of sinewaves, no less) is much more effectively and reliably performed, for which ICs are readily available.



nilton61

This can be done with a 4066 quad analog switch and some capacitors

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