Help designing a variable capacitance Colpitts Oscillator

Discussion in 'The Projects Forum' started by red007, Apr 11, 2011.

  1. red007

    Thread Starter New Member

    Apr 11, 2011
    Calculate the dimensions of a rod or loop antenna so that it generates a
    capacitance of 2pF when the hand is 4 inches away.

    I used C0=e0*A/d, but then it asks

    Plot the capacitance of the antenna as function of the distance of the hand. Given this what should the value of C2 be, so that C1 effectively controls the oscillations? Can C2 be made the variable capacitance in your design if you use your hand as the other plate of a tunable capacitor?

    The plot I got, but I have no idea about the rest.