ISRO Electrical Engineering (EE) 2015 - Question 24

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The frequency of oscillations of transistorized Colpitts Oscillator having tank circuit parameters C1 = 150 pF, C2 = 1.5 nf and L = 50 µH is

  • A. 500 kHz
  • B. 3.26 MHz
  • C. 1.927 MHz
  • D. 63.5 kHz

Answer: C. 1.927 MHz

Explanation: Ceq = 150×1500/1650 = 136.4 pF; f = 1/(2π√(50 µH × 136.4 pF)) ≈ 1.93 MHz.

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