GATE EC question library

At

300 \mathrm{~K}

, for a diode current of

1 \mathrm{~mA}

, a certain germanium diode requires a forward bias of

0.1435 \mathrm{~V}

, whereas a certain silicon diode requires a forward bias of

0.178 \mathrm{~V}

. Under the conditions stated above, the closest approximation of the ratio of reverse saturation current in germanium diode to that in …

A particular green

\text{LED}

emits light of wavelength

5490 \text{ A}

. The energy bandgap of the semiconductor material used there is (Planck's constant =

6.626 \times 10^{-34} \mathrm{~J-s})

When the gate-to-source voltage

\left(\mathrm{V}_{\mathrm{GS}}\right)

of a MOSFET with threshold voltage of

400 \; \mathrm{mV}

, working in saturation is

900 \; \mathrm{mV}

, the drain current is observed to be

1 \mathrm{~mA}

. Neglecting the channel width modulation effect and assuming that the MOSFET is operating at saturation, the drain …

If

\mathrm{P}

is Passivation,

\mathrm{Q}

is

n

-well implant,

\mathrm{R}

is metallization and

S

is source/drain diffusion, then the order in which they are carried out in a standard

n

-well CMOS fabrication process, is

An amplifier without feedback has a voltage gain of

50

, input resistance of

1 \mathrm{~K} \Omega

and output resistance of

2.5 \mathrm{~K} \Omega

. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of

0.2

is

In the amplifier circuit shown in the figure is the values of

R_{1}

and

R_{2}

are such that the transistor is operating at

\mathrm{V}_{\mathrm{CE}}=3 \mathrm{~V}

and

\mathrm{I}_{\mathrm{C}}=1.5 \mathrm{~mA}

when its

\beta

is

150.

For a transistor with

\beta

of

200,

the operating point …

The oscillator circuit shown in the figure is has an ideal inverting amplifier. Its frequency of oscillation (in

\mathrm{Hz}

) is

The output voltage of the regulated power supply shown in the figure is

The action of a

\text{JFET}

in its equivalent circuit can best be represented as a

If the

\text{op-amp}

in the figure is idea, the output voltage Voult will be equal to

Three identical amplifiers with each one having a voltage gain of

50,

input resistance of

1 \mathrm{~K} \Omega

and output resistance of

250 \; \Omega

, are cascaded. The open circuit voltage gain of the combined amplifier is

An ideal sawtooth voltage waveform of frequency

500 \mathrm{~Hz}

and amplitude

3 \mathrm{~V}

is generated by charging a capacitor of

2 \; \mu \mathrm{F}

in every cycle. The charging requires

The circuit shown in the figure has

4

boxes each described by inputs

P, Q, R

and outputs

Y, Z

with

\begin{array}{l} Y=P \oplus Q \oplus R \\ Z=R Q+\bar{P} R+Q \bar{P} \end{array}

The circuit acts as a

If the functions

W, X, Y

and

Z

are as follows

\begin{array}{l} W=R+\bar{P} Q+\bar{R} S \\ X=P Q \bar{R} \bar{S}+\bar{P} \bar{Q} \bar{R} \bar{S}+P \bar{Q} \bar{R} \bar{S} \\ Y=R S+\overline{P R+P \bar{Q}+\bar{P} \cdot \bar{Q}} \\ Z=R+S+\overline{P Q+ \bar{P} . \bar{Q} . \bar{R} + P \bar{Q} . \bar{S}} \end{array}

Then

A

4

bit ripple counter and a

4

bit synchronous counter are made using flip flops having a propagation delay of

10 \mathrm{~ns}

each. If the worst case delay in the ripple counter and the synchronous counter be

R

and

S

respectively, then

The DTL, TTL, ECL and CMOS families of digital

\mathrm{IC}_{\mathrm{s}}

are compared in the following

4

columns …

The circuit shown in the figure is a

4

bit

\text{DAC}

The input bits

0

and

1

are represented by

0

and

5 \mathrm{~V}

respectively. The

\text{OP AMP}

is ideal, but all the resistances and the

5 \mathrm{~V}

inputs have a tolerance of

\pm 10 \%

. The specification (rounded to the nearest multiple of

5 \%

) for the tolerance …

The circuit shown in the figure converts

In the circuit shown in the figure

\mathrm{A}

is a parallel-in, parallel-out

4

bit register, which loads at the rising edge of the clock

C

. The input lines are connected to a

4

bit bus,

W.

Its output acts as the input to a

16 \times 4

ROM whose output is floating when the enable input

E

is

0.

A partial table of the contents of …

In an

8085

microprocessor, the instruction CMP

B

has been executed while the content of the accumulator is less than that of register

B

. As a result