Experiment wise viva questions Basic Electronics Lab
PN-Junction Diode:
- What is a diode?
- What are the applications of diode?
- Draw the symbol of PN junction diode and mark anode and cathode.
- Define threshold voltage or cut in voltage of a diode.
- define dynamic and static resistances of a diode.
- Cut-in voltage of Si diode is…………………
- Cut-in voltage of Ge diode is…………………
- Draw the VI characteristics of PN junction diode.
- What is forward bias of a junction diode? Explain with circuit diagram.
- What is reverse bias of a junction diode? Explain with circuit diagram.
- Define space charge or Depleted region of a diode?
- Explain the working operation of a junction diode in forward and reverse bias.
- p type material means………….. Give some examples of N-type materials
- n type material means…………Give some examples of P-type materials
- Ideal diode acts as short circuit under forward bias. Or draw the equivalent circuit of ideal diode in forward bias.
- Ideal diode acts as open circuit under reverse bias. Or draw the equivalent circuit of ideal diode in reverse bias.
- Draw the equivalent circuit of practical diode in forward bias and reverse bias.
- What are the differences between avalanche and Zener break down.
- What are intrinsic and extrinsic impurities?
- Differentiate a conductor, semiconductor and dielectric material.
- Write the diode current equation.
Zener Diode:
- What is Zener diode? Define how it is different from ordinary PN diode.
- What are the applications of Zener diode?
- Draw the symbol of Zener diode and mark anode and cathode.
- Define Zener breakdown.
- What is the Zener breakdown voltage value———–.
- How Zener diode is acting as a voltage regulator?
- What is the cut-in voltage of a Zener diode————.
- Draw the equivalent circuit of Zener diode?
- Zener diode operates in reverse bias? Why?
- Explain avalanche multiplication in detail.
- Explain Zener multiplication in detail.
- Give two differences between avalanche and Zener multiplication.
Half Wave rectifier and Full wave Rectifier (same questions are valid for FWR)
- What is a rectifier? How diode is used as a rectifier?
- Define ripple factor?
- What is the need for filter at the output of a rectifier?
- What is percentage of regulation?
- Give the ripple factor values for HWR and FWR (read comparison table between HWR and FWR).
- What is the efficiency of HWR and FWR? Give values.
- What are the advantages of FWR over HWR?
- What are the disadvantages of HWR?
- What are the drawbacks of FWR?
- Define PIV of a diode.
- PIV of HWR and FWR are………..
- why we need rectifiers?
- where we use rectifiers ?
- what are the differences between rectifier and converter?
CE/CB characteristics:
- Draw the symbol of transistor.
- Draw pnp and npn transistor symbols.
- What are three configurations of a BJT?
- Draw the circuits of CE, CB and CC configurations.
- What is CE or Grounded Emitter configuration?
- What is CB or Grounded Base configuration?
- What is CC or Grounded Collector configuration?
- What are input and output characteristics of BJT?
- Draw input and output characteristics of CE configuration.
- Draw input and output characteristics of CB configuration.
- What are the applications of CE and CB transistors?
- Comparison table of CE, CB and CC configurations in terms of input resistance, output resistance, voltage gain, current gain and applications.
- What are the three terminals of a transistor?
- Define doping levels of emitter, base and collector.
- Define early effect in CB transistor.
- The majority carriers in pnp transistor are………..
- The majority carriers in npn transistor are………..
- Why BJT is called as bipolar device?
- Is BJT a uni polar or bipolar device?
- What are the applications of transistors?
- what is the phase difference between input and output waveforms of CE transistor( ans: 180o)
- What is the phase difference between input and output waveforms of CB transistor ( ans: 0o or 360o).
- Why NPN transistor is preferred over PNP transistor?
- Why CE is preferred over other combinations in voltage amplifiers?
- Define saturation, cutoff, active regions of a transistor?
- What is cutoff region of operation of a transistor?
- Read about comparison tables of Si, Ge transistors for active cutoff and cutin and saturation voltages.
JFET:
- What is FET or JFET?
- What are the differences between BJT and FET?
- Why BJT is called as Current controlled device?
- Why FET is called as Voltage controlled device?
- Draw the symbol of FET?
- Symbols of N-channel and p channel FETs.
- Differences between N- channel and P- channel FET’s?
- Draw the input or output characteristics of JFET?
- What are the meanings of source drain and gate?
- What are the applications of FET?
- What are the advantages of FET over BJT?
- Draw h-parameter model of a BJT in CE/CB configurations?
- Define pinchoff voltage of a FET?
- Explain about linear saturation and breakdown regions of CE/CB output characteristics?
- Explain about linear saturation and breakdown regions from drain or output characteristics of JFET
- Define 4 h-parameters of BJT in CE configuration?
- Draw the equivalent circuit of FET?
- define µ, gm , rd in FET? what is the relation between those three parameters?
- define trans conductance and drain resistance of FET?
- The input resistance of a JFET is very high in Mega ohms.
- Working of JFET.
- Applications of JFET.
Operational Amplifier:
- What is Operational Amplifier?
- What are the ideal characteristics of Op-amp?
- What are the applications of op-amp?
- What is inverting amplifier?
- What is non inverting amplifier?
- What is meant by open loop and closed loop op-amp?
- Identify the feedback resistor in inverting and non inverting amplifiers (ans:Rf).
- What are the advantages of op-amp over feedback amplifiers?
- Define slew rate?
- Draw circuits of integrator and differentiator using op-amp
- Draw adder and subtractor circuits using op-amp.
- What is virtual ground in op-amp circuits?
- What is open loop gain of an ideal op amp?
Oscillators:
RC Phase Shift Oscillator:
- Mention the two conditions required for oscillations in RC phase shift oscillator?
- Give the formula for frequency of oscillations in RC phase shift oscillator?
- The phase produced by a single RC network is RC phase shift oscillator?
- RC phase shift oscillator uses positive feedback or negative feedback?
- The phase produced by basic amplifier circuit in RC phase shift oscillator is?
- What is the difference between damped oscillations and un damped oscillations?
- What are the applications of RC phase shift oscillator?
- How many resistors and capacitors are used in RC phase shift feedback network?
- How the Barkhausen’s criterion is satisfied in RC phase shift oscillator
- Mention the basic reason for any oscillations?
- What is meant by Barkhausen’s criterion?
- Audio frequency range is————
- RC phase shift oscillator is ——–
- Oscillator is a circuit operates on internal input power supply yes or no?
- Define an oscillator?
- Oscillator did not take any external input yes or no?
- Type of feedback used in oscillators is——-
- Radio frequency range is———–
- Show that single RC section provides a phase shift of 60 degrees.
- Positive feedback causes instability yes or no?
- In oscillators loop gain must be————–
- In oscillators the overall phase shift produced by the circuit is————
- Feedback gain 𝛽 must be less than———–
COLPITTS AND HARTLEY’S OSCILLATORS:
- What are the advantages of hartley’s and colpitts oscillators over RC phase shift oscillator?
- Applications of Colpitts and Hartleys oscillators are—–.
- Colpitts oscr uses ———- in its feedback network.
- Hartleys oscr uses ———–in its feedback network.
- Define mutual inductance—–
- colpitts and hartleys ocsillators are used at ———— frequencies.
- Give the formula for frequency of oscillations in Colpitts oscillator.
- Give the formula for frequency of oscillations in Hartley’s oscillator?
SINGLE STAGE CE AMPLIFIER:
- What is the phase difference between input and output waveforms of a CE amplifier?
- What type of biasing is used in the given circuit?
- What is the effect of emitter bypass capacitor on frequency response of a CE amplifier?
- What is the effect or importance of coupling capacitor?
- Why source resistance Rs is used in the input side?
- What are the different regions of operation of a BJT?
- The phase difference of input and output in CB amplifier?
- CE amplifier is voltage or current amplifier?
- Draw the equivalent h-parameter model of a CE amplifier?
- Why NPN transistor is preferred over PNP transistor?
- What is the effect of bypass capacitor over stability of the CE amplifier?
- The CE amplifier is in voltage divider bias or in fixed bias configuration?
- The values of hfe,hie,hoe and hre in CE configuration are—————-.
- hfe,hie,hoe and hre are called as——————–.
- What do you mean by loading effect?
- What are the practical applications of single stage CE amplifier?
- How do you know the amplifier is single stage CE amplifier?
- Why this circuit is called RC coupled amplifier?
- What is the operating point in CE amplifier from the design specifications?
- Quiescent conditions means——–
- D.C conditions are for———
- What is the relationship between collector current and base current?
- Does β and hfe are one and the same?
- Why coupling capacitor Cb is connected in reverse (-,+) at the input side and Cc is connected in forward(+,-) at the output side?
- How do u know a transistor is working in cut off region?
- Write VBE(active),VBE(sat),VBE(cutoff) values of a Si and Ge transistors
- Transistor meaning is———
- Define frequency response of a CE amplifier?
- Define voltage gain of a CE amplifier?
- Units of gain as a ratio are———-
- Units of gain in logarithim is———
- Magnitude response and frequency response are one and the same say yes or no?
- Define bandwidth?
- What are 3 dB frequencies?
- Define cutoff frequencies?
- BW is approximately equal to fH justify?
- Gain is constant in————-
- Semi logarithmic graph is linear or non linear graph?
- Stability factor is a function of—–
- In the circuit R1 and R2 are used for——–
- The feedback type that Re and Ce introduces in the circuit is———–(Ans: negative feedback).
- Negative feedback increases stability yes or no(Ans:yes).
- CB amplifier provides more band width than CE amplifier justify?
Note: Read advantages and disadvantages and applications of every experiment.
ALL THE BEST
Prepared by P.Lakshmi Prasanna