Question

iz Instructions Question 12 1 pts 12 R2 Tir 11 A L1 RIS The figure shows the circuit diagram of an oscillator using an ideal voltage amplifier with amplification A. The values of the circuit components are, R1 = 580 ohms, R2 = 1000 ohms, L1 4.0 millihenry, L2 - 2.0 millihenry. The frequency of oscillation in kHz is determined as nearest to which of the following answers: 10 KHZ O 40 KHz 60 kHz O 80 kHz 155 kHz Next i

Answer 1

Vm on By using voltage divison vule, the feedback factor.is B= whille Rg + JWbgt (wn, ll R,) Simplification, above 'B' becomes. B = Ri Ryan.com, nyt j [wR, (4x+4;) + WR24] According to Barkhausen Criterion, for the Oscillator to work , the phase of feedback factol should be JWLIRI where m=1,2,3.. 2B = 211n The phase of feedback factors above is LB = 98 - tani'. WR, (472) + WR, L = 21T or o R, R₂- while 90° ie tan - WR, (Ly+23) + WR24 R,R₂ - o w L, L2 Tan 90 = 01- WR, (Lat L) + WR₂4 R, R₂ whil, R, R₂ - While so R, R2 Lila 11 How R, R2 LiL2 wa R, R2 2 UT 211 LILL - (580) (1000) (4x103) (2x103) .: frequency of oscillation of an 42,853.779 H3 = 42 KHZ nearer to 40KHZ