-9- Question 6 Soalan 6 A Wien-Bridge oscillator with a lead-lag circuit is shown in Figure 8. [Suatu pengayun Wien-Bridge dengan litar mendulu-mengekor ditunjukkan dalam Gambarajah 8.] D D. 6.8 V 6.8 V R; 47k02 R 100 kn C R w 0.015 pF LOKN RS 1.0k C 0.0154F Figure 8 [Gambarajah 8) (a) Find the frequency of oscillation. [Dapatkan frekuensi pengayun.] (4 Marks/Markah) (6) Determine the necessary value of R, so that the circuit will oscillate. Neglect the forward resistance of D, and D2. (Tentukan nilai perintang R, supaya litar befungsi sebagai pengayun. Abaikan rintangan ke depan D and Dy] (7 Marks / Markah) (c) Explain the purpose of R3, D, and Dz. [Terangkan peranan R, D, and D:] (8 Marks / Markah) -9- Question 6 Soalan 6 A Wien-Bridge oscillator with a lead-lag circuit is shown in Figure 8. [Suatu pengayun Wien-Bridge dengan litar mendulu-mengekor ditunjukkan dalam Gambarajah 8.] D D. 6.8 V 6.8 V R; 47k02 R 100 kn C R w 0.015 pF LOKN RS 1.0k C 0.0154F Figure 8 [Gambarajah 8) (a) Find the frequency of oscillation. [Dapatkan frekuensi pengayun.] (4 Marks/Markah) (6) Determine the necessary value of R, so that the circuit will oscillate. Neglect the forward resistance of D, and D2. (Tentukan nilai perintang R, supaya litar befungsi sebagai pengayun. Abaikan rintangan ke depan D and Dy] (7 Marks / Markah) (c) Explain the purpose of R3, D, and Dz. [Terangkan peranan R, D, and D:] (8 Marks / Markah)