Operational Amplifier Practice Test

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• The circuit output measures -2 V and Vin is 0.2 V; the magnitude of the closed-loop gain is
• In a voltage follower, are external gain-setting resistors required?
• Which statement best describes the essential feedback path in a voltage follower?
• In an inverting amplifier, why is the virtual ground not a real ground?
• Why is proper power-supply decoupling essential in op-amp circuits?
• In an op amp comparator circuit, hysteresis primarily does what to input sensitivity?
• Explain the trade-off between closed-loop gain and bandwidth and how GBW constrains the relationship.
• In op-amp noise analysis, which statement is correct?
• If the input voltages of an op-amp are identical and the output voltage is 0Vdc. The op-amp is
• To generate a test signal lower in amplitude than can be supplied by your signal generator, use
• Define input offset voltage, and explain how it affects the output in non-inverting and inverting configurations.
• The inverting input of this op amp is at virtual ground.
• Which statement about the summing amplifier is true?
• Which statement about peak detectors at very fast input signals is most accurate?
• What issue do improved precision rectifier topologies aim to avoid?
• In the comparator circuit, the output voltage Vo is what relationship to the input Vin?
• From the circuit values, Vo equals which of the following?
• In a quad op-amp chip, how many individual op-amps are present?
• In a transimpedance amplifier, how does the output voltage relate to the input current and the feedback resistor?
• Op-amps possess
• In circuit applications, the closed-loop gain is directly related to the op-amp what?
• Which of the following is NOT a packaging material used for op amp packages?
• A typical property of a differential amplifier is that the output is proportional to the difference between which signals?
• In a summing amplifier, increasing any one input while the others are constant will primarily affect the output through which mechanism?
• Which statement best describes real-world op-amp non-ideal parameters and their impact on circuit performance?
• Which statement correctly describes the virtual ground concept at the inverting summing node?
• Unity gain in an inverting configuration requires
• Which statement about a unity-gain buffer is accurate?
• Compare LM741 and LM358 in terms of input common-mode range, output swing, supply requirements, and typical applications.
• If an op-amp has a unity-gain bandwidth of 1 MHz and you design a closed-loop gain of 5, what is the approximate closed-loop bandwidth?
• As s1 is toggled back and forth, v0 switches between.
• To achieve higher accuracy when converting a PWM signal to an analog voltage, which approach is recommended?
• How does a transimpedance amplifier convert current into voltage?
• In the inverting amplifier, the node where the input resistor connects to the op-amp's inverting input is held at what type of voltage due to negative feedback?
• What is CMRR and why is it important in instrumentation amplifiers?
• In the comparator circuit CR1, CR1 conducts as a zener and rectifier diode.
• If V1 and V2 are equal in value, Vo equals which expression?
• On the inverting amplifier, the summing junction is at
• What is the transfer function of a difference amplifier with resistors R1, R2, R3, R4 and the usual matching condition?
• Which statement about op amp packaging materials is true?
• The bandwidth of an inverting amplifier is measured at the
• To adjust the output offset voltage of an op-amp, connect circuit inputs to
• When both inputs are equal, the op-amp is described as
• In an open-loop configuration, op-amps are what?
• Which statement applies to a voltage follower circuit configuration?
• In a comparator configuration, the threshold voltage is determined by which quantity?
• Regarding the LF441 dual or quad style package, which statement is true?
• Which of the following active notch topologies can realize a sharp notch with adjustable Q?
• In the given threshold circuit, the threshold voltage Vth equals VsAT divided by (RH/R1).
• The amplifier bandwidth of this circuit is less than 100 Hz.
• Explain the Wien bridge oscillator principle and the condition for sustained oscillation.
• Which parameter defines notch depth and sharpness in an active notch filter?
• What are limitations of precision rectifiers at very low input voltages, and how can they be mitigated?
• In this circuit, R2 decreases the input impedance of the op-amp.
• For low frequencies, the AC gain of an inverting amplifier is determined by the ratio of which two resistors?
• Define power-supply rejection ratio (PSRR) and how it affects circuit performance.
• When two equal signals are applied to the inputs of a balanced closed-loop op-amp circuit, the signal is what?
• Which term describes the error voltage associated with input bias currents?
• What issues arise when driving a purely capacitive load with an op-amp and how can you mitigate them?
• In an inverting unity-gain amplifier, which statements are true when R3 = R1?
• When would you choose a rail-to-rail input/output op-amp?
• In a negative-feedback op-amp circuit, the input differential voltage tends to
• In a three-op-amp instrumentation amplifier, derive the overall gain expression in terms of RG, R1, and the differential-stage resistors R3 and R4 (assuming ideal matching).
• Based on the circuit information, the value of Rf is
• In a circuit with Rin = 5 kΩ and RF = 45 kΩ in an inverting amplifier, the closed-loop gain magnitude is
• Which configuration yields a differentiator, and what is the transfer function and a practical limitation?
• When looking at an op amp from the top, the pin count orientation is:
• What is the output expression for an inverting summing amplifier with multiple inputs V1, V2, … using input resistors R1, R2, … and a feedback resistor Rf?
• In an inverting amplifier, the closed-loop gain magnitude equals
• Full-power circuit performance refers to bandwidth.
• In a practical op-amp circuit, the closed-loop gain is mainly set by which components?
• In a non-inverting summing amplifier, what is the differential input voltage in linear operation?
• Based on the non-inverting circuit, Vo equals which expression?
• Which technique reduces the impact of temperature drift on op-amp parameters in precision applications?
• Which statement is true?
• Which statement correctly describes how source impedance affects op-amp noise performance?
• An op-amp configured as an open loop comparator does what?
• A common mode input voltage can represent which of the following in a circuit?
• What primarily sets the gain of an inverting summing amplifier?
• The inverting input voltage is approximately 0 V, referred to as virtual ground.
• The voltage divider circuit block provides which of the following voltages?
• Which term describes the error voltage caused by input bias currents?
• The two inputs of an op-amp are marked (-) and (+). These inputs provide what?
• Which are the key assumptions of the ideal op-amp model used in basic analysis?
• How do input bias currents and source resistances contribute to output offset in op-amp circuits, and how can this error be minimized?
• In open-loop operation, op-amps exhibit what kind of sensitivity to input voltage variations?
• Explain the basic topology of a three-op-amp instrumentation amplifier and give the gain expression in terms of R1, Rg, and the differential stage resistors.
• In a noninverting amplifier, the closed-loop gain is
• In an ideal op-amp, what is the input impedance?
• With Rf = 50 kΩ and Rin such that the gain magnitude is 10, Rin = 5 kΩ yields a gain of
• The condition where the inverting and non-inverting inputs are equal due to negative feedback is known as what?
• Which of the following op-amp statements is false?
• Define noise gain and explain its role in op-amp stability and closed-loop design.
• What condition ensures proper common-mode rejection in a classic four-resistor difference amplifier?
• The small current at the input of an op amp is described as
• Offset current changes caused by drift produce which effect in the circuit's output?
• What is the general function of a difference amplifier?
• A capacitor placed in parallel with the feedback resistor of an op-amp circuit causes the bandwidth to
• For a TO-type metal can package, pin 1 is located adjacent to what feature?
• What does the concept of a virtual short imply in an op-amp circuit with negative feedback?
• Which statement is false regarding the circuit gain factor?
• Voltage comparators perform as
• In a typical inverting op-amp configuration, increasing the feedback resistor value tends to
• What factors limit the speed of a peak detector using an op-amp, and how can you mitigate slow recovery?
• In a non-inverting summing amplifier, which statement about the inverting input is true?
• For a Multiple-Feedback (MFB) active filter, what do component values primarily determine?
• An inverting amplifier uses
• What effect does adding a resistor in parallel with the feedback capacitor have on stability in a differentiator circuit?
• If a positive voltage is applied to the input of a noninverting op amp, the output voltage is
• In a transimpedance amplifier, Vout is proportional to the input current with a negative sign: Vout = -Iin × Rf.
• What is the closed-loop gain formula for an inverting amplifier, and what is the role of the virtual ground?
• In an inverting summing amplifier, what happens to the polarity of the summed voltages?
• What is the closed-loop gain of a non-inverting amplifier and how does it relate to the feedback resistor network?
• What limitation do conventional op-amps have compared with rail-to-rail types?
• In a circuit where Vo = 4 × (V2 - V1) and R3 = R4, what is the given value for both resistors in the example?
• What is the effect of a capacitive load on op-amp stability and what practical measures help ensure stable operation?
• Compare a plain comparator with a Schmitt trigger in terms of noise immunity and switching behavior.
• In voltage comparator circuits CR1 Vo is clamped at -5.1 Vdc, generating a negative feedback voltage, and improving circuit response.
• For the LF441 in a dual or quad style package, null pins are:
• Which statement about a voltage follower is false?
• If Rin is halved while Rf remains fixed, the closed-loop gain magnitude doubles.
• Given a Schmitt trigger with Vout_high = +Vsat, Vout_low = -Vsat and a divider ratio α = R2/(R1+R2), what are the upper and lower switching thresholds?
• Quad op-amp is a single package with how many individual op-amps?
• In the example, Vo equals 2xV2 or 2xV1. Which option reflects this statement?
• In a Sallen-Key low-pass filter, what role does the feedback path play in setting Q and gain?
• Outline a design approach for an op-amp-based active notch filter to reject a known interference frequency.
• What combination most determines the speed of recovery in a peak detector?
• Which statement about a difference amplifier is false?
• In designing an active notch filter, which statement best describes how the notch center frequency is determined?
• A typical differential amplifier circuit constructed with an op amp is subject to which limitations?
• In a voltage follower, the feedback path is from the output to which input?
• In the ideal op-amp model, what is the relationship between the currents entering the two input terminals?
• The input of a noninverting op amp is applied to the
• In a precision rectifier circuit, when Vin is negative, what happens to the diode and the output?
• If V2 exceeds V1, what is the sign of the output Vout in a standard difference amplifier?
• If Vo equals V2 minus V1, which resistor condition ensures this relationship?
• Define slew rate and describe its impact on waveform reproduction in high-speed op-amp circuits.
• Increasing the feedback resistor RF in a noninverting amplifier while Rin is fixed causes the gain to
• What happens when an op-amp output saturates and why is recovery time important in circuit design?
• Which statement best describes the impact of open-loop configuration on the output without feedback?
• In a three-op-amp instrumentation amplifier, how does mismatching resistors R3 and R4 affect the output?
• For the discussed inverting summing amplifier, the output voltage Vo is expressed as which of the following?
• What is a practical consequence of poor CMRR in an instrumentation amplifier?
• Explain the gain-bandwidth product concept and how it governs the closed-loop bandwidth for a given op-amp.
• A properly balanced (trimmed) op amp with grounded inputs has an output voltage:
• Which statement about summing amplifiers is true?
• Why is a leakage path added in practical differentiator or integrator circuits and how does it affect DC behavior?
• What is a voltage follower and what advantages does it offer in signal conditioning?
• When looking at an op amp from the bottom, the pin count orientation is:
• If R1 is increased in an inverting amplifier, the circuit gain and bandwidth
• In a precision rectifier circuit, which statement best explains the role of the op-amp in achieving near-ideal rectification at small input voltages?
• In an inverting amplifier, the closed-loop gain is given by the ratio of the feedback resistor to the input resistor with a negative sign. This is
• What is the output impedance of an ideal op-amp?
• For an inverting amplifier to reproduce input signals with a wide range of frequencies, the amplifier should possess
• The simplest voltage follower configuration requires which connection?
• Define common-mode input range and explain why it matters for single-supply operation.
• Which is a typical reason to use an inverting summing amplifier?
• Which method is used to convert a PWM signal to an analog voltage using op-amps and passive components?
• In a standard op-amp with negative feedback, the amplifier operates in its linear region when
• To set the output offset voltage to zero, connect the circuit inputs to the
• In an inverting op-amp with a DC output offset, clipping can be asymmetric.
• Which statement about a gain-of-one amplifier is true?
• In a linear closed-loop op-amp, the differential input voltage is approximately what value?
• A voltage follower circuit has which of the following characteristics?
• For the summing amplifier discussed, the circuit gain is set to which value?
• Which of the following is NOT listed as an op amp package type?
• How is hysteresis implemented in a Schmitt trigger using positive feedback, and how do you compute the upper and lower thresholds in a common configuration?
• Typical voltage follower circuits are used as which of the following?
• For a positive input, the output of an inverting amplifier is
• Which statement best describes capacitive loading's effect on op-amp stability?
• Which of the following is NOT a characteristic of an op-amp?
• What primarily limits the performance of a peak detector circuit that uses an op-amp and a diode?
• The -3 dB point is used to define the bandwidth boundary.
• An ideal voltage follower has
• Which statement correctly distinguishes transimpedance amplifiers from transconductance amplifiers?
• In a Multiple-Feedback (MFB) active filter, what is the primary function of the feedback capacitors?
• Which of the following actions will increase the circuit output voltage in an inverting amplifier?
• An ideal op-amp in a voltage follower circuit has
• Which circuit illustrates a difference amplifier?
• If the gain of an inverting op amp is very high, the circuit
• The inverting unity-gain amplifier has a gain equal to which ratio, and what happens to the input signal?
• An inverting summing amplifier can perform which operation on multiple input signals?
• For a general-purpose practical op-amp, the open-loop voltage gain is about what?
• Explain how temperature drift affects op-amp parameters such as offset voltage and bias currents and what design strategies mitigate this drift.
• Which statement is false? an inverting summing amplifier does not alter the polarity of the summed voltages
• The small current at the input of an op amp is called
• Based on the circuit configuration, Vo equals which expression?
• To increase the circuit gain, you should decrease the value of Rin.
• In a noninverting amplifier, the input signal is applied to the
• In a Sallen-Key low-pass filter, the op-amp typically acts as what?
• If the circuit load resistor is varied within design limits, the circuit voltage gain remains the same.
• What resistor relationships are required in a differential amplifier circuit to achieve Vout = (R2/R1)(V2 − V1)?
• A non-inverting summing amplifier cannot scale or weight input signals. Which of the following statements is false?
• If an input voltage of 0.2 V is applied to the circuit, the output voltage is
• Based on the provided information, Vo is essentially what?
• What is the transfer function of an ideal op-amp integrator with input resistor Rin and feedback capacitor Cf, and how does a parallel feedback resistor modify it?
• In an active notch filter, how do Q factor and notch depth relate, and which component adjustments influence Q?
• If the circuit values are as specified, what is Vo?
• If R1 through R4 are equal, Va equals the average of the input voltages.
• Slew rate refers to
• In a properly designed difference amplifier, common-mode signals are which of the following?
• From the bottom view, the pin count direction is
• In this circuit, if Vo equals (R4/R1) × (V2 − V1), which of the following must be true?
• Describe how a peak detector using an op-amp and a diode operates.
• In a follower configuration, the offset voltage of the LF441 op-amp need not be trimmed because it is what?
• Based on the circuit information, the correct currents are IL = 1 mA, IF = 1 mA, Iin = 1 mA.
• If the input voltage of an inverting amp is positive, which description best matches the output?
• An inverting summing amplifier can be configured to
• To configure this circuit for summation of the input voltages, change the value of the indicated (1 kΩ) resistor to which value?
• What is the closed-loop gain of a voltage follower?
• Which statement about the difference amplifier is true when v2 is greater than v1?
• The term describing equal voltages at the inputs due to feedback is?
• What practical modification is commonly made to an ideal differentiator circuit to improve stability, and what is its effect?
• If a difference amplifier has resistor mismatch from the ideal matching condition, what is the likely effect on the output?
• In this circuit, the output voltage Vo must be
• The non-inverting input of an op-amp is designated by which symbol?
• The -5.1 Vdc clamp in CR1 prevents the output from going below -5.1 Vdc. This is an example of which behavior?
• In an ideal inverting amplifier, the magnitude of the voltage gain is equal to the ratio of the feedback resistor to the input resistor.
• If the feedback resistor is doubled from its original value while the input resistor remains the same and the initial gain is 75, what is the new gain?
• Which of the following is NOT listed as an op amp package type?