# 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.
42.53, 0.85 μA
40.91, 0.58 μA
40.91, 0.58 μA
41.10, 0.39 μA
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
31 V
32 V
insufficient data
none of these
Explanation:

RMS value = 965 = 31.064 Volt.

43.
Work function of oxide coated cathode is much lower than that of tungsten cathode.
True
False
Explanation:

Therefore emission current from oxide coated cathode is more.

44.
The word enhancement mode is associated with
tunnel diode
MOSFET
JFET
photo diode
Explanation:

MOSFET may be depletion mode or enhancement mode.

45.
In which region of a CE bipolar transistor is collector current almost constant?
Saturation region
Active region
Breakdown region
Both saturation and active region