1. State, with reasons, whether the following statements are True or False.

i) Ideal voltage source has infinite internal resistance.

ii) Transformer is a passive device hence it cannot increase the voltage.

iii) Field effect transistor (FET) is a current controlled device.

iv) Forward biasing of a semiconductor junction diode reduces its energy band gap.

v) Amplifier with common collector mode offers maximum voltage gain.

vi) Ripple factor of a center tapped full wave rectifier is greater than that of a bridge rectifier, which uses four diodes.

vii) Operational amplifier in non-inverting mode cannot amplify negative signals.

viii) IC LM380 is a small signal amplifier used to amplify the voltage.

ix) Largest decimal number represented by a 2-digit hex number is 99.

x) In a CRO sweep generator output is given to the vertical deflection plates.

2. a) Use superposition principle to find the current flowing through R2 in Fig.1. (6) Fig. 1

b) Explain with a neat diagram application of p-n junction diode as a peak voltage detector.

3. a) A series LCR circuit with L = 400 mH, C = 20 nF and R = 250 ? is connected to an AC source of 65 V.

Calculate the resonance frequency and Q of the circuit. What is the current flowing through the circuit and voltage across the capacitor at resonance frequency?

b) Which processes are responsible for the charge carrier transport in a semiconductor? Which of these govern in the case of a bulk semiconductor when no potential is applied?

4. a) Refer to the universal bias shown in Fig. 4.11 of your study material. If Vcc = 10V, R₁ = R₂ = R_C = R_E = 10kΩ, V_BE = 0.7V and β = 100, calculate V_B, V_E, I_E, I_B, V_C and V_CE.

b) h-parameters of a single stage CE amplifier are given as h_ie = 1 kΩ , h_re = 3 × 10^-4, h_fe = 60 and h_oe = 25 μA/V. Calculate A_i, A_v and Z_out with r_s =100Ω and r_L =10kΩ.

5. a) State the Barkhausen criterion for sustained oscillation. Explain the operation of Colpitt Oscillator. For a Colpitt oscillator with 10 MHz frequency determine the equivalent capacitance, C forming tank circuit with 0.1 mH inductor.

b) In a voltage regulator circuit, the output voltage under no load condition is 12V while under full load it is 11.8V. Over the full range of input voltage variation the nominal voltage output of 12V varies by 50 mV. Calculate percentage line and load regulation.

6. a) Draw a circuit of a non-inverting amplifier with gain 1 using op-amp. Draw the output voltage curve of this circuit for a step input of 5V amplitude and 50 kHz frequency, if the slew rate of the op-amp is 0.5 V/μs. (Use proper scale on the time axis to illustrate the effect of slew rate).

b) Design and draw the circuit of a three channel op-amp adder with channel gains of -5, -10 and -15 respectively.

7. a) Draw a circuit of amplifier of gain 50 using IC 380. Use the non-inverting terminal as input signal terminal.

b) Design and draw the circuit of a regulated power supply using LM 317 to provide 30V output.

8. a) Design and draw the circuit diagram of a Mod-6 ripple counter.

b) A 4-bit DAC produces 22 mV output for a digital input of 1011. What is the resolution for this DAC? Find out Vout for 0101.

9. a) Explain the working of D-flip flop. How does it differ from a D-latch?

b) Explain the construction and working of a differential amplifier type EVM.