Analog Electronics MCQs 2026

Transformer coupling in amplifiers provides

1. Ainfinite bandwidth without leakage inductance✓
2. Belimination of all AC coupling✓
3. CDC isolation and impedance matching between stages✓
4. Ddirect connection of base to collector✓

Total harmonic distortion (THD) measures

1. Aonly DC offset magnitude✓
2. Bonly noise floor without harmonics✓
3. Charmonic content relative to fundamental in output✓
4. Dslew rate limit only✓

Differential amplifier rejects

1. Adifferential signals between inputs✓
2. Bcommon-mode signals applied equally to both inputs✓
3. Csignals on inverting input only without any gain✓
4. Dsupply voltage variations as common-mode always without CMRR limit✓

Cascode amplifier configuration improves

1. Ahigh-frequency response by reducing Miller effect✓
2. Bonly DC offset without frequency benefit✓
3. Cinput impedance to near zero always✓
4. Doutput to be digital logic level only✓

Negative feedback in amplifiers generally

1. Aincreases distortion without exception✓
2. Beliminates need for power supply✓
3. Creduces distortion and stabilizes gain at the cost of bandwidth✓
4. Draises open-loop gain✓

Bandwidth of an amplifier is often defined between

1. Alower and upper half-power (−3 dB) frequencies✓
2. Bonly DC gain point✓
3. Conly harmonic distortion threshold without frequency✓
4. Dsupply ripple frequency only✓

Bypass capacitor across emitter resistor in CE stage

1. Aincreases AC gain by shorting emitter resistance at signal frequency✓
2. Breduces AC gain to zero always✓
3. Cblocks AC to the base✓
4. Dreplaces collector load✓

Coupling capacitor between amplifier stages blocks

1. AAC signal entirely without DC block✓
2. Bonly high frequencies above 1 MHz always✓
3. Cfeedback path unconditionally✓
4. DDC bias while passing AC signal✓

Class AB amplifier improves on Class B by

1. Aeliminating all feedback✓
2. Bproviding small bias so both devices conduct near crossover✓
3. Cusing only single transistor✓
4. Doperating only in cutoff always✓

Class B push-pull amplifier each transistor conducts for

1. Afull 360° each simultaneously✓
2. Bapproximately 180° of the cycle✓
3. C90° only without crossover region✓
4. D0° so no output ever✓

Class A amplifier conducts

1. Aonly 180° of cycle✓
2. Bless than 90° only✓
3. Conly during negative half-cycle✓
4. Dfor the full 360° of the input cycle✓

Power amplifier is designed to deliver

1. Aonly microvolt signals to high-impedance probes✓
2. Blogic levels to CMOS gates only✓
3. Csignificant power to the load efficiently✓
4. DDC offset calibration only✓

Voltage amplifier ideally increases

1. Acurrent without voltage change✓
2. Bpower factor of mains only✓
3. Csignal voltage with minimal loading of source✓
4. Dfrequency of carrier without gain✓

Rail-to-rail op-amp output stage allows

1. Aoutput fixed at mid-supply only✓
2. Binput only on positive rail without negative✓
3. Coperation without power supplies✓
4. Doutput swing close to both supply rails✓

Schmitt trigger using op-amp provides

1. Apure integration without thresholds✓
2. Bzero output swing always✓
3. Cinfinite CMRR without resistors✓
4. Dhysteresis to avoid chatter on noisy input signals✓

Gain-bandwidth product of an op-amp is approximately constant for

1. Aall frequencies without rolloff✓
2. Bsingle-pole dominant response in closed-loop designs✓
3. CDC offset only✓
4. Dcomparator hysteresis only✓

Input bias current of op-amp is

1. AAC ripple on output only✓
2. Bslew rate in V/μs✓
3. Cclosed-loop gain in dB only✓
4. Daverage DC current required by the input terminals✓

Op-amp comparator output saturates to

1. Aalways mid-rail without saturation✓
2. Banalog value proportional to difference in linear mode always✓
3. Cnear positive or negative supply depending on input difference✓
4. Dzero without supply✓

Differentiator op-amp circuit uses

1. Aonly resistors in both paths✓
2. Binductor in feedback without capacitor✓
3. Ccapacitor at the input and resistor in feedback✓
4. DZener diode for clipping only✓

Integrator op-amp circuit uses

1. Ainductor in input only without capacitor✓
2. Bcapacitor in the feedback path✓
3. Cresistor-only feedback for integration✓
4. Ddiode bridge in feedback✓

Unity-gain buffer (voltage follower) uses

1. Apositive feedback only✓
2. B100% negative feedback from output to inverting input✓
3. Cno feedback connection✓
4. Dopen-loop operation only✓

Common-mode rejection ratio (CMRR) measures

1. Adifferential gain only without common signal✓
2. Boutput short-circuit current only✓
3. Csupply voltage ripple only✓
4. Dability to reject equal signals applied to both inputs✓

Freewheeling diode across an inductive load prevents

1. Alarge voltage spikes when switching current off✓
2. Bforward voltage drop from existing✓
3. Coscillator startup without feedback✓
4. Dop-amp input offset drift✓

Slew rate of an op-amp limits

1. Amaximum rate of change of output voltage✓
2. BDC gain only✓
3. Cinput bias current only✓
4. Dcommon-mode rejection at DC only✓

Transconductance gm of a FET relates

1. Asmall-signal drain current change to gate-source voltage change✓
2. Bcollector current to base current only✓
3. Cdiode forward voltage to current only✓
4. Doutput voltage to supply voltage only✓

Depletion-mode MOSFET differs from enhancement mode in that it

1. Anever conducts without positive VGS always✓
2. Bhas no channel at manufacture✓
3. Cuses only PNP structure✓
4. Dconducts with VGS = 0 and requires negative VGS to turn off (n-channel)✓

Enhancement-mode n-channel MOSFET conducts when

1. AVGS exceeds threshold voltage positively✓
2. BVGS is zero without channel ever✓
3. CVDS alone creates channel without gate✓
4. Dgate is left floating for heavy conduction✓

MOSFET is a

1. Avoltage-controlled device via gate-source voltage✓
2. Bcurrent-controlled device like BJT base✓
3. Cmajority carrier device only in depletion mode always without exception✓
4. Dbipolar device with two PN junctions✓

Early effect in a BJT causes

1. Agate threshold to decrease only in MOSFET✓
2. Bcollector current to increase slightly with collector-emitter voltage✓
3. Cdiode PIV to double✓
4. Dinductor core saturation✓

Common-collector (emitter follower) configuration has

1. Alow input and high output impedance✓
2. Bhigh input impedance and low output impedance✓
3. Cvoltage gain much greater than 100 typically✓
4. Dinverted output relative to input always✓

BJT operates in saturation when

1. Acollector-base junction is reverse biased only✓
2. Bemitter is open circuit✓
3. Cgate voltage is below threshold✓
4. Dboth junctions are forward biased and VCE is small✓

In a common-emitter BJT amplifier, base current controls

1. Adrain current without gate voltage✓
2. Bonly emitter reverse leakage✓
3. Clarge collector current via current gain β✓
4. Dop-amp offset voltage directly✓

Rectifier diode selection must consider

1. Aonly LED color wavelength✓
2. Bforward current rating, PIV and switching speed for the application✓
3. Conly op-amp slew rate✓
4. Donly flip-flop clock frequency without power✓

Varactor diode capacitance varies with

1. Areverse bias voltage✓
2. Bforward current only without voltage dependence✓
3. Ctemperature only without bias✓
4. Dgate threshold in MOSFET sense✓

Tunnel (Zener) breakdown dominates in heavily doped junctions at

1. Avery high reverse voltage only above 100 V always✓
2. Bforward conduction region only✓
3. Clower reverse voltages (typically below about 5 V in silicon)✓
4. Donly in germanium without silicon✓

Avalanche breakdown in a diode occurs when

1. Aforward bias exceeds knee slightly only✓
2. Bgate oxide ruptures in MOSFET✓
3. Conly tunneling without multiplication✓
4. Dminority carriers accelerate and create impact ionization✓

Diode dynamic resistance rd is defined as

1. Aslope of V-I curve at the operating point (dv/di)✓
2. Breverse saturation current only✓
3. Cmaximum forward current rating✓
4. Dthermal voltage times beta✓

Schottky diode has lower forward voltage drop than PN junction diode because

1. Ait uses only indirect bandgap silicon always✓
2. Bit has no depletion region ever✓
3. Cmetal-semiconductor junction has smaller barrier height✓
4. Dit operates only in Zener breakdown✓

LED emits light when

1. Areverse breakdown occurs without recombination✓
2. Belectrons and holes recombine at the PN junction✓
3. Conly thermal heating without injection✓
4. Dgate voltage controls channel only like MOSFET✓

Ripple factor of a rectifier output indicates

1. Aonly DC average without AC content✓
2. Breverse breakdown voltage margin✓
3. Ctransistor beta value✓
4. Damount of AC component relative to DC component✓

Full-wave bridge rectifier requires

1. Atwo diodes and center tap always✓
2. Bfour diodes and no center-tapped transformer✓
3. Cone diode only✓
4. Dsix diodes in star connection✓

Half-wave rectifier output contains

1. Apure DC without any ripple✓
2. Bonly one polarity of the input AC waveform✓
3. Cboth polarities equally✓
4. Donly high-frequency harmonics without fundamental✓

Peak inverse voltage (PIV) rating of a rectifier diode is

1. Amaximum forward current only✓
2. Bpower dissipation at room temperature only✓
3. Cjunction capacitance at zero bias✓
4. Dmaximum reverse voltage the diode can withstand without breakdown✓

Zener diode is primarily used for

1. Arectification in forward region only✓
2. Boscillation without feedback✓
3. Ccurrent amplification like a BJT✓
4. Dvoltage regulation in reverse breakdown region✓

Reverse saturation current in an ideal silicon diode at room temperature is

1. Aequal to forward current always✓
2. Bvery small (nanoampere range)✓
3. Cin the ampere range typically✓
4. Dproportional to forward voltage squared only✓

A semiconductor diode conducts heavily when

1. Areverse biased above breakdown always without limit✓
2. Bunbiased at thermal equilibrium only for heavy conduction✓
3. Cforward biased beyond knee voltage✓
4. Dconnected in parallel with reverse diode only✓

Audio power amplifier heat sink sizing depends on

1. Aonly voltage gain in dB✓
2. Bonly input bias current in pA✓
3. Conly LED forward voltage✓
4. Dpower dissipation and thermal resistance to ambient✓

Emitter degeneration resistor without bypass

1. Amaximizes AC gain unconditionally✓
2. Bprevents any collector current flow✓
3. Cstabilizes bias and reduces gain but improves linearity✓
4. Dreplaces the need for coupling capacitor✓

Op-amp input offset voltage causes

1. Asmall DC output error even with zero input signal✓
2. Binfinite bandwidth always✓
3. Coscillation without any feedback✓
4. Dinput impedance to become zero✓

Non-inverting amplifier closed-loop gain is

1. A1 + Rf/R1✓
2. B−Rf/R1 only✓
3. CRf/R1 without unity term✓
4. Dzero always with feedback✓

Inverting amplifier closed-loop gain is

1. A1 + Rf/Rin without sign inversion✓
2. BRf × Rin product only✓
3. Cindependent of feedback resistors✓
4. D−Rf/Rin✓

Virtual short between inputs of op-amp in negative feedback means

1. Aboth inputs are physically shorted externally✓
2. Binputs carry equal large current always✓
3. Cvoltage difference between inputs is approximately zero✓
4. Doutput is always saturated✓

Ideal operational amplifier has

1. Azero gain and zero input impedance✓
2. Binfinite open-loop gain, infinite input impedance and zero output impedance✓
3. Cfinite gain of unity only always✓
4. Doutput impedance equal to 50 Ω always✓

Safe operating area (SOA) of a transistor specifies

1. Aonly maximum power at DC only without pulse duty✓
2. Bpermissible combinations of voltage and current without damage✓
3. Conly beta at one current point✓
4. Donly op-amp bandwidth✓

FET is preferred in high-input-impedance amplifier front ends because

1. Agate draws negligible DC current✓
2. Bcollector draws maximum base current✓
3. Cemitter is always forward biased heavily✓
4. Ddrain current equals gate current always✓

Darlington pair provides

1. Aunity voltage gain only without current gain✓
2. Bnegative input impedance always✓
3. Coscillation without feedback guaranteed✓
4. Dvery high current gain with two cascaded transistors✓

Channel length modulation in MOSFET is analogous to

1. AEarly effect in BJT✓
2. BZener breakdown in diodes only✓
3. Chysteresis in Schmitt trigger only✓
4. Dsampling aliasing only✓

Slew rate of an op-amp limits

1. Amaximum rate of change of output voltage✓
2. BDC gain only✓
3. Cinput bias current only✓
4. Dcommon-mode rejection at DC only✓