Electronics and Communication Engineering - Electronic Devices and Circuits

41. 

Calculate the stability factor and change in IC from 25°C to 100°C for, β = 50, RB/ RE = 250, ΔIC0 = 19.9 nA for emitter bias configuration.

A. 42.53, 0.85 μA
B. 40.91, 0.58 μA
C. 40.91, 0.58 μA
D. 41.10, 0.39 μA

Answer: Option A

Explanation:

SICO = (1 + β).

51. = 42.53

ΔIC = (SICO).ΔICO

= 42.53 x 19.9 nA

= 0.85 μA.


42. 

A periodic voltage has following value for equal time intervals changing suddenly from one value to next... 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, -5, -10 etc. Then rms value of the waveform is

A. 31 V
B. 32 V
C. insufficient data
D. none of these

Answer: Option A

Explanation:

RMS value = 965 = 31.064 Volt.


43. 

Work function of oxide coated cathode is much lower than that of tungsten cathode.

A. True
B. False

Answer: Option A

Explanation:

Therefore emission current from oxide coated cathode is more.


44. 

The word enhancement mode is associated with

A. tunnel diode
B. MOSFET
C. JFET
D. photo diode

Answer: Option B

Explanation:

MOSFET may be depletion mode or enhancement mode.


45. 

In which region of a CE bipolar transistor is collector current almost constant?

A. Saturation region
B. Active region
C. Breakdown region
D. Both saturation and active region

Answer: Option B

Explanation:

It is used as amplifier when it operates in this region.