Electric Circuits Answers

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.

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

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

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 three channel op-amp adder with channel gains of
−5, −10 and −15 respectively.

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) 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.

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) h-parameters of a single stage CE amplifier are given as hie = 1 kW , hre = 3 × 10−4,
hfe = 60 and hoe = 25 μA/V. Calculate Ai, Av and Zout with rs =100W and rL =10kW.