Which among the below mentioned oscillators does not adopt

Question

1. In the Wien bridge oscillator with R₁ = R₂ = R and C₁ = C₂ = C, a ratio of R₃ to R₄ will provide sufficient loop gain for the circuit to oscillate.

• 0
• 0.5
• 1
• 2

2. Which among the below mentioned oscillators does not adopt any kind of feedback mechanism?

• Phase-shift oscillator
• Wein bridge oscillator
• UJT relaxation oscillator
• Voltage controlled oscillator
• UJT relaxation oscillator

3.  If A+1=1 and A.1=A, then the value of (A+B)(A+C) is equal to

• A+BC
• AC+B
• AB+C
• A+B

4. If V(Ref)=1.25 V, R₁=3 Kilo-ohm, R₂= 1 Kilo-ohm and unregulated input voltage=20 V, then the duty cycle of the phase of the base of the transistor used in a switching regulator circuit is

• 2%
  2.50%
  20%
  25%

5. A communication channel of bandwidth 75 kHz is required to transmit binary data at a rate of 0.1 Mb/s using raised-cosine pulses.
The roll-ff factor is

• 5
• 0.05
• 1.5
• 0.5

6. An op-amp has a common mode gain of 0.01 and a differential mode gain of 100.Its CMRR in db would be

• 60
• 100
• 120
• 80