Electronics and Communication Engineering - Analog Electronics

6. 

In the circuit figure LED will be on when v1 is

A. less than 6 V
B. more than 6 V
C. less than 12 V
D. more than 12 V

Answer: Option B

Explanation:

Voltage input to inverting input is . Therefore, vi should be more than 6 V.


7. 

A differential amplifier consists of two CB amplifiers.

A. True
B. False

Answer: Option B

Explanation:

It consists of two CE amplifiers.


8. 

Figure shows a portion of linear v - i characteristics of diode. If applied voltage is + 6 V, the current will be

A. 42 mA
B. 48 mA
C. 51 mA
D. 54 mA

Answer: Option D

Explanation:

.


9. 

A power transistor dissipates 5 W. If ambient temperature is 30° and case to air thermal resistance is 10° C/W, the case temperature is

A. 80°C
B. 20°C
C. 32°C
D. 305°C

Answer: Option A

Explanation:


10. 

An R-C coupled amplifier has mid-frequency gain of 200 and a frequency response from 100 Hz to 20 kHz. A negative feedback network with β = 0.2 is incorporated into the amplifier circuit, the Bandwidth will be

A. 50 kHz
B. 20 kHz
C. 100 kHz
D. infinite

Answer: Option C

Explanation:

B.W. = fH' - fL' .