SparkFun Forums 

Where electronics enthusiasts find answers.

For the discussion of Arduino related topics.
By michael1978
#197966
n1ist wrote: Fri Jan 19, 2018 7:21 am For that schematic, I would suggest having the arduino control a servo and use it to turn the tuning capacitor.
/mike
one man he told me like this but i dont know how to add a new component this varacator
this the answer
You should have stated up front and immediately that this circuit was copied from this website. I hardly think it is worth the effort, but to interface this circuit to an Arduino you will need a digital-to-analog converter and one or more varactor diodes, such as this one, an SVC236-TB-E from ON Semiconductors and available from Mouser. You wire two or more of these varactor diodes in parallel and connect them in parallel across the tuning capacitor, VC1, in series with a largish-valued DC-blocking capacitor. You will then need to reverse-bias the varactor diodes with a separate, isolated, DC power source whose output voltage is controlled by the digital-to-analog converter connected to the Arduino. Easy-peasy, then just add some software... er, sorry, a sketch... as software is called in the Arduino world.
By michael1978
#197967
n1ist wrote: Fri Jan 19, 2018 7:21 am For that schematic, I would suggest having the arduino control a servo and use it to turn the tuning capacitor.
/mike
yes you right, i did not know so much about varacator