# Linear Integrated Circuits December-2011

UNIT – I

1.Draw the schematic diagram of non-inverting OP AMP with voltage series feedback; explain it and derive the expression for the

(i) voltage gain

(ii) Input Resistance

(iii) Output Resistance.

OR

1. Explain the following applications of OPAMP :

(i) Voltage follower

(ii) Adder

(iii) Comparator

(iv) Inverting Amplifier

UNIT-II

2 (a) Design a triangular wave generator using a comparator circuit with integrator circuit to generate a triangular wave of frequency 5 KHz., Assume peak to peak output voltage is 5V and (±Vsat) = (± 14 V).

(b) Design a R-C phase shift oscillator which gives the sinusoidal waveform of 600 Hz.

OR

2 (a) Draw and explain with suitable diagram : Voltage to frequency converter.

(b) Explain the working of quadrature oscillator with suitable diagram.

UNIT – III

3. (a)Draw and explain with suitable diagram First-order low pass Butterworth filter.

(b)Design a wide band pass filter with fL=500 Hz and fH = 2KHz, and a pass band again = 5 for both sections of filter. Also determine the value of Q for the filter.

OR

(a). Write short note on “switched capacitor filter”.

(b) Design a narrow bandpass filter with a centre frequency fc = lKHz, Q = 5, Af = 8. Change the centre frequency to 2KHz, keeping AF and Bw constant.

UNIT – IV

4. Explain the operation of PLL with the help of block diagram.

Also explain linear model of second order PLL.

OR

4    Briefly describe the role of PLL in the following

(i)  AM detector

(ii) Tracking filter

UNIT – V

5 (a) Explain the ‘Tour quadrant Multiplier”.

(b) Design a 555 a stable multivibrator to generate an output pulse with a frequency fQ = 5KHz and a duty cycle of 60%. Given Vcc = 15V and Ic min = 1mA.

OR

5. (a) In the schmitt trigger, RL = 100 q , R2 = 56 Kq , Vin = 2V peak to peak sine wave, and the power supply voltage – + 15 V. Determine the upper and lower threshold voltage, Vut and Vit. The maximum output voltage swing is ± 14 V.

(b) Write short note on Monostable multivibrator.