ISRO Scientist or Engineer Electronics May 2017
For the following questions answer them individually
Two initially identical samples A & B of pure germanium are doped with donors to concentrations of $$1 \times 10^{20}$$ and $$3 \times 10^{20}$$ respectively. If the hole concentration in A is $$9 \times 10^{12}$$ then the hole concentration in B at the same temperature will be
Transistors $$Q_{1}$$ and $$Q_{2}$$ are identical and $$\beta >> 1$$ in the circuit shown in the figure below. The output voltage is $$(V_t = 0.026 V)$$:
Consider following 8085 microprocessor program
MVI A, DATA1
ORA A
JM DISPLAY
OUT PORT1
CMA
DISPLAY : ADI 01H
OT PORT1
HLT
If DATA1 = A7H, the output at PORT1 is
In an ADC, the minimum Effective Number of Bits (ENOB) requires to represent each quantization level to achieve Signal to Noise and Distortion Ratio (SINAD) of 70 dB is
Two isotropic antennas are separated by a distance of two wavelengths. If both the antennas are fed with currents of equal phase and magnitude, the number of lobes in the radiation pattern in the horizontal plane are
The half-power beam width (HPBW) of an antenna in the two orthogonal planes are $$120^\circ$$ and $$40^\circ$$ respectively. The directivity of the antenna is approximately equals to
Two resistors $$R_{1}$$ and $$R_{2}$$ (in ohms) at temperatures $$T_{1} K_{1}$$ and $$T_{2} K_{2} $$respectively, are connected in series. Their equivalent noise temperature is
