ISRO Scientist/Engineer ECE Solved Papers

Which of the following functions have a jump discontinuity at $x=0$?

What would be the output of the following circuit, if a positive going unipolar pulse with an amplitude greater than Vref, is applied at the input?

What is the output voltage across the 900 ohm load in the circuit given below?

What is the transfer function of the network given below?

A voltage regulator having $Vref=1.25V$ needs to generate 5V output. Assume that $Iadj=100\mu A$ and $R1=10kohm$. What should be value of R2?

$1\text{ cm}^3$ of pure Germanium at $20^\circ\text{C}$ contains about $4.2 \times 10^{22}$ atoms, $2.5 \times 10^{13}$ free electrons and $2.5 \times 10^{13}$ holes. 0.001% of Arsenic doping donates an extra $10^{17}$ free electrons in the same volume. The approximate number of holes in one $\text{cm}^3$ in the doped semiconductor under equilibrium condition is :

Measurement of Hall coefficient enables the determination of :

Silicon is not suitable for fabrication of light emitting diodes because it is :

The band gap of elements arranged in ascending order is :

The following statements are made for NMOS & PMOS

1. The carrier mobility in NMOS is higher
2. PMOS require less area than NMOS
3. NMOS circuits are smaller than PMOS
4. PMOS are faster in switching.

Of these, the true statements are:

The following statements are made for FETS

1. In n-channel depletion mode MOS in the active region, the control voltage $V_{GS}$ is negative.
2. NMOS in depletion mode is cut off for $V_{GS}=0$
3. NMOS in enhance mode is cut off for $V_{GS}=0$
4. There is no path between source and drain in the enhancement mode

Of these, the true statements are:

Special handling precautions should be taken when working with MOS devices. The statement which is not true is :

If the input to the circuit of Figure is a sine wave, then the output will be:

A high gain OpAmp has $R_f = 10^5\;\Omega$ & $R_i = 10^3\;\Omega$. The correct statement is :

For various types of oscillators, the correct statement is:

For Butterworth & Chebyshev filters, the correct statement is :

In a feedback series regulator circuit, the output voltage is regulated by controlling the

In a fullwave rectifier circuit with centre tap transformer, if voltage between one end of secondary winding and centre tap is 300V peak, then PIV (peak inverse voltage) is

The rms value of the periodic waveform as shown in Figure is

The approximate equivalent resistance between terminals A and B for the following infinite ladder network comprising of 1 Ω & 2 Ω resistors is :

If the step response to the input step amplitude of 1 V is given by $V_o(t)=(1-e^{-t/RC})$, the network can be represented by :

For a parallel RC circuit as shown in figure, $R=20~\Omega$ & $C=0.9~\text{pF}$, which is to be matched to $50~\Omega$ over a bandwidth,

$$\int_{0}^{\infty} \ln\frac{1}{|\Gamma|} \, d\omega \le \frac{\pi}{R \cdot C}$$

The circuit has to be matched over 6 GHz to 18 GHz. What is the very best Γ that can be achieved:

In this circuit, V is a sinusoid input with freq f, current i contains:

The effect of phase error of local oscillator on spectral components in coherent detection of SSB Amplitude modulated signal is:

The maximum transmission power efficiency of DSB-C Amplitude Modulation is: