Trouble with variable capacitor values.

Discussion in 'General Electronics Chat' started by Jack_Rider, Apr 5, 2009.

  1. Jack_Rider

    Thread Starter New Member

    Apr 5, 2009
    1
    0
    Please can someone help me out about the problem of determining variable capacitor values? I'm trying to make a radio circuit and i don't ever get a clue as to what value of Inductance i should use because there isn't any value marked on the variable capacitors. Thanks.?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, you could use a known inductance in parallel with the unknown capacitance to create a resonant tank circuit. Use that in the feedback path of a high-speed opamp and measure the output frequency.
     
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