ELECTRONICS CIRCUIT

1. The input power to a device is 10,000 W at a voltage of 1000 V. The output power is 500 W and the output impedance is 20. Find the voltage gain in decibels.

• A.-13 dB
• B. -20 dB
• C.-10 dB
• D.-3 dB

2. Two stages have voltage gains of 100 and 200. The total decibel voltage gain is

• A. 46 dB
• B. 66 dB
• C. 86 dB
• D. 106 dB

3. A two-pole high-pass active filter would have a roll-off rate of

• A. 40 dB/decade
• B. -40 dB/decade
• C. 20 dB/decade
• D.-20 dB/decade

4. The voltage gain of an op amp is unity at the

• A. Cutoff frequency
• B. Unity-gain frequency
• C. Generator frequency
• D. Power bandwidth

5. If funity is 10 MHz and midband open-loop voltage gain is 1,000,000, then the open-loop cutoff frequency of the op-amp is

• A. 10 Hz
• B. 20 Hz
• C. 50 Hz
• D. 100 Hz

6. The center frequency of a bandpass filter is always equal to

• A. The bandwidth
• B. Geometric average of the cutoff frequencies
• C. Bandwidth divided by Q
• D. 3-dB frequency

7. Determine the quality factor of a bandpass filter with a lower cutoff frequency of 20.1 kHz and an upper cutoff frequency of 20.3 kHz.

• A. 10
• B. 10.1
• C. 101
• D. 202

8. For a passive bandpass filter using RLC circuit, which of the following below is the expression for its bandwidth?

• A. BW=1/(2*pi*sqrt(L*C))
• B. BW=1/(2*pi**C)
• C. BW=R/(2*pi*L)
• D. BWR/(2*pi*f*L)

9. The bandwidth in a filter equals the critical frequency.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

10. The common-mode voltage gain is

• A. Smaller than the voltage gain
• B. Equal to the voltage gain
• C. Greater than the voltage gain
• D. None of the above