**B.E Forth Semester May/June 2010**

**Linear IC’s and Applications**

__PART-A__**1**a. Define the following parameters:

i) Input offset voltage

ii) CMRR

iii) Slewrate.

Mention their typical values for op-amp 741.

**(06 Marks)**b. Sketch the circuit of two-input inverting summing amplifier. Explain the operation of the circuit and derive the equation for the output voltage.

**(08 Marks)**c. A non-inverting amplifier is to amplify a 100mV signal to a level of 3V. Using a 741 op-amp, design a suitable circuit.

**(06 Marks)****2**a. Sketch the circuit of a high Z

_{in}capacitor coupled voltage follower. Briefly explain its operation and show that the input impedance is very high compared to the capacitor coupled voltage follower.

**(06 Marks)**

b. Explain how the upper cutoff frequency can be set for inverting and non-inverting amplifiers.

**(06 Marks)**c. Design Z

_{in}capacitor coupled voltage follower using an op-amp having lower cutoff frequency of 50Hz and maximum input bias current of 500nA. The load resistance is 3.6KΩ. If the open loop gain is 2 x 10^{5}, find ideal value of input impedance of the circuit.**(08 Marks)**

**3**a. With a neat sketch, explain the working of a lag compensation network. Show how it affects the frequency response of an op-amp?

**(08 Marks)**

b. List the precautions to be observed for op-amp circuit stability.

**(08 Marks)**c. Determine the upper cutoff frequency and the maximum distortion free output amplitude for a voltage follower when a 741 op-amp is used.

**(04 Marks)****4**a. With a neat sketch, explain the working of a precision voltage source using op-amp with a zener diode. Derive an expression relating V

_{O}and V

_{Z}.

**(08 Marks)**

b. Draw the circuit of an instrumentation amplifier. Explain its characteristics. Also show how the voltage gain can be varied.

**(08 Marks)**c. Determine the range of resistance R

_{G}for a LH0036 IC instrumentation amplifier to give a voltage gain adjustable from 30 to 300.**(04 Marks)**

__PART-B__**5**a. Draw and explain an op-amp sample and hold circuit with signal, control and output waveforms.

**(08 Marks)**

b. With a neat sketch, explain the working of Wein-Bridge Oscillator circuit.

**(06 Marks)**

c. Using a 741 op-amp with a supply of ±12V, design a phase-shift oscillator to have an output frequency of 3.5KHz.

**(06 Marks)****6**a. What are the advantages of active filters over passive filters?

**(04 Marks)**

b. Sketch the circuit of a second order active high pass filter, explain its working.

**(08 Marks)**

c. An inverting Schmitt trigger circuit is to have UTP = 0 and LTP = 2.5V. Design a suitable circuit using a bipolar op-amp and a ±18V supply.

**(08 Marks)****7**a. Explain the application of IC 723 as a basic low voltage regulator.

**(06 Marks)**

b. Explain the principle of switch mode power supplies. Enumerate their advantages and disadvantages.

**(08 Marks)**c. Using 7805 design a current source to deliver 0.2A current to a 22Ω, 10W loads. Take quiescent current as 4.2 mA.

**(06 Marks)****8**a. Draw and explain the functional diagram of 555 timer.

**(06 Marks)**

b. With a sketch, explain the working of R-2R ladder DAC.

**(08 Marks)**c. An 8-bit ADC outputs all 1’s when V

_{i}= 2.55V. Find its: i) Resolution in mV/LSB and

ii) Digital output when V

_{i}= 1.28V.**(06 Marks)** ******************

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