PDC
UNIT-1(Linear wave shaping)
1. The waveform which preserves its form when transmitted through a linear network is a___________. [ b ]
(a)Sine wave (b) Step signal (c) impulse signal (d) ramp signal
2. An RC high pass circuit has R= 1kΩ and C=0.5 μF. Its lower cutoff frequency is [ b]
(a) zero (b) 318.3 Hz (c) 1kHz (d) infinity
3. For a integrator, if input is square wave then the output waveform is _____ [ a]
(a) Impulse (b) Sawtooth wave (c) Triangular wave (d) Both a and c
4. A ringing circuit has a quality factor Q=24. This circuit will ring for how many number of cycles? [ c]
(a) 24 (b) 12 (c) 8 (d) 6
5. The rise time of the output of a low pass RC circuit is given by [c ]
(a) 2.2 RC (b) 0.35/fH (c) 2.2τ (d) all the above
6. What is the response of step input to a high pass RC circuit [ a ]
a) V e-t/RC b) V (1- et/RC) c) V et/RC d) V(1- e-t/RC )
7. When RC high pass circuit act as a differentiator? [ a]
a) RC<<T b) RC>>T c)RC=T d)RC=0
8. What is the name of the circuit which converts square wave in to spikes [ c]
a) Low pass RC b) Bi stable multi c) High pass RC d) Monoshot
section II: fill in the blanks
9. For DC input signal capacitor C acts as a open circuit
10. The average value of the output value of an RC high pass circuit is Zero
11. In RC integrator circuit the output is taken across capacitor
12. -------------is the condition for an RC high pass circuit to acts as a differentiator.
13. Time constant of RL circuit is L/R
14. The process of converting pulses into spikes is called Tilt
15. Write the relationship between time constant and tilt? Linear wave shaping
UNIT-2 : Non linear wave shaping
1. A comparator is a basic building block in a system used to analyze the -------- distribution of noise generated in active device [ b]
a) Both frequency and phase b) Amplitude c) Phase d) Frequency
2. Zener diode has ---------- temperature coefficient [ b]
a) sometimes positive and sometimes negative b) Only negative.
c) Both positive and negative d) Only positive
3. A clamping circuit is also called as ____________. [ c ]
(a) dc restorer (b) dc reinserter (c) both a and b (d) none of the above
4. A clipping circuit consists of ___________. [ c]
(a) Resistor (b) Diode (c) both a and b (d) c and capacitor
section II: fill in the blanks
5. The clamping theorem is given by Af/Ar=Rf/R
6. When the diode is forward biased it acts as closed switch
UNIT-III: SWITCHING CHARACTERISTICS OF DEVICES
1. Common base configurations is little used because [ C]
a) High voltage gain b) High current gain c) It has low input impedance d) High input impedance
2. The Vce (sat) of Si n-p-n transistor at 27 c is [ B ]
a) 0.7 v b) 0.3 v c) 0.8 v d) 0.1 v
3. Turn off time of the transistor is = ------- [A ]
a) toff =tf +ts b) toff =tf +ton c) toff =tfd +ts d) toff =ton +ts
Unit-IV: multivibrators
Section-I: Multiple choice questions
1. Monostable multivibrators generates [ b ]
a) Pulse wave form b) Ramp signal c) Sine wave d) Square wave
2. A sinusoidal waveform can be converted to a square waveform by using _______ [ c ]
(a) Astable multivibrator (b) Bitable multivibrator (c ) Schmitt trigger (d) None of the above
3. A Schmitt trigger is a __________. [ a]
(a) counter (b) Voltage to frequency converter (c) Comparator (d) None of the above
Section-I: Fill in the blanks:
1. A bistable multivibrator is used for 0.5MHz
2. The time constant of a monostable multivibrator is 2.2τ = 2.2RC = 0.35/f2
3. _______________ circuit is used to generate the sequence of pulses which are regularly spaced in time
4. No of quasi stable states of astable is 2
5. The expression of pulse width for monostable multivibrator is (T/2RC) X 100
Prepared by G.swathi