Operational Amplifiers

Which of the following is NOT a characteristic of an ideal operational amplifier?

What is the closed-loop voltage gain (Av = vo/vin) for a basic inverting amplifier with an input resistor R1 and a feedback resistor R2, assuming an ideal op-amp?

In the analysis of ideal op-amp circuits with negative feedback, what is the 'summing-point constraint'?

What is the closed-loop voltage gain (Av = vo/vin) for a noninverting amplifier with resistors R1 (from inverting input to ground) and R2 (feedback), assuming an ideal op-amp?

What is the primary effect of connecting an op-amp circuit with positive feedback instead of negative feedback?

A special inverting amplifier shown in Figure 13.6 uses a T-network in the feedback path with R1 = 1 kOhm, R3 = 1 kOhm, R2 = 10 kOhm, and R4 = 10 kOhm. What is the voltage gain (Av) of this circuit?

What is the input impedance of a standard inverting amplifier with input resistor R1 and feedback resistor R2?

An op-amp circuit known as a voltage follower is created by connecting the output directly to the inverting input and applying the input signal to the noninverting input. What is the voltage gain of this circuit?

A certain op amp has a DC open-loop gain (A0OL) of 100,000 and an open-loop break frequency (fBOL) of 40 Hz. What is its gain-bandwidth product (ft)?

An op amp has a DC open-loop gain of 100,000 and a gain-bandwidth product of 4 MHz. If it is used in a noninverting amplifier with a closed-loop DC gain of 10, what is its closed-loop bandwidth (fBCL)?

What is the full-power bandwidth (fFP) of an LM741 op amp with a slew rate (SR) of 0.5 V/microsecond and a guaranteed maximum output amplitude (Vom) of 12 V?

What is the term for the nonlinear limitation of an op-amp where the magnitude of the rate of change of the output voltage is limited?

In an inverting amplifier with R1 = 10 kOhm and R2 = 100 kOhm, what is the maximum DC output voltage component due to a bias current (IB) of 100 nA?

To cancel the effects of DC bias currents in an inverting amplifier with input resistor R1 and feedback resistor R2, what value of resistor (Rbias) should be added in series with the noninverting input to ground?

What is the primary function of an instrumentation-quality differential amplifier compared to a simpler single-op-amp differential amplifier?

For an op-amp integrator circuit with input resistor R and feedback capacitor C, what is the expression for the output voltage vo(t)?

For an op-amp differentiator circuit with input capacitor C and feedback resistor R, what is the expression for the output voltage vo(t)?

When designing op-amp circuits, what is a primary problem associated with using very large resistance values (e.g., in the megaohm range)?

What is the magnitude of the Butterworth transfer function |H(f)| at the cutoff frequency fB?

How is a fourth-order Butterworth lowpass filter typically implemented using Sallen-Key circuits?

A non-inverting amplifier is designed for a voltage gain of 10. According to Section 13.4, if standard 5-percent-tolerance resistors are used, approximately what is the expected unit-to-unit variation in the gain of the amplifier?

An op-amp summer circuit is shown in Figure 13.7. What is the expression for the output voltage (vo) in terms of the input voltages (vA, vB) and resistor values (RA, RB, Rf)?

What is the primary reason that negative feedback is used in most operational amplifier circuits?

In a noninverting amplifier, what is the theoretical input impedance of the circuit under the ideal-op-amp assumption?

A real op amp has a finite open-loop gain that is a function of frequency, often modeled as AOL(f) = A0OL / (1 + j(f/fBOL)). What does the term fBOL represent?

An op-amp is used in a noninverting amplifier circuit as shown in Figure 13.23 with R1 = 1 kOhm, R2 = 3 kOhm, and a load resistor RL > 10 kOhm. The op-amp is an LM741 with a maximum output voltage range of -12 V to +12 V. If the input is a sinusoid with a peak voltage of 5 V, what will the output waveform look like?

An op-amp with a maximum output current of plus or minus 40 mA is used in the circuit of Figure 13.23 (gain = 4). If the input is a 1 V peak sinusoid and the load resistance RL is 50 Ohm, what is the cause of distortion in the output?

Which of the three DC imperfections (bias current, offset current, offset voltage) is modeled as a small DC voltage source in series with one of the op-amp inputs?

In a fourth-order Butterworth lowpass filter designed by cascading two Sallen-Key sections, what is the overall DC gain (H0) of the filter?

An inverting amplifier is built with R1 = 10 kOhm, R2 = 100 kOhm. The op-amp has a maximum offset voltage of 2 mV. What is the range of the DC output voltage component caused solely by this offset voltage?

What is the relationship between the closed-loop DC gain (A0CL) and the closed-loop bandwidth (fBCL) for a noninverting amplifier using a given op-amp?

Why is it generally impractical to design op-amp circuits with very small feedback resistances (e.g., less than 100 Ohms)?

An op-amp is configured as an integrator with R = 10 kOhm and C = 0.1 microFarad. If a constant input voltage of 1 V is applied at t=0, what is the output voltage at t=2 milliseconds?

What is the term for the average of the two DC input bias currents (IB+ and IB-) flowing into an op-amp?

A differential amplifier has input signals v1 and v2. The differential input signal (vid) is defined as v1 - v2. How is the common-mode signal (vicm) defined?

An op-amp is used in a non-inverting configuration. To achieve a voltage gain of 131, and using a 10 kOhm resistor for R1, what value is required for the feedback resistor R2 based on the formula derived in Exercise 13.6?

What is the primary characteristic of the output voltage of an ideal inverting amplifier?

A certain op-amp has a maximum output voltage range from -4 to +4 V, a maximum current of 10 mA, and a slew rate of 5 V/microsecond. For a frequency of 1 MHz and a load of 1 kOhm, what is the maximum possible peak output voltage without distortion?

What is the term for the condition at the input of an op-amp with negative feedback where the differential voltage is forced to zero, but no current flows, which can be thought of as if a short circuit exists but without current flow?

To design a fourth-order lowpass Butterworth filter using two cascaded Sallen-Key sections, what K values (DC gains) are required for the two stages?

What is the primary characteristic of an op-amp integrator's output if the input is a square wave?

In a simple single-op-amp differential amplifier as shown in Figure 13.33, with R4/R3 = R2/R1, what is the output voltage (vo)?

An inverting amplifier is designed with R1 = 49.9 kOhm and R2 = 499 kOhm to amplify a signal from a source with a variable internal resistance (Rs) that is always less than 500 Ohm. What is the approximate voltage gain (vo/vs) of this configuration?

For a noninverting amplifier, what is the minimum possible closed-loop voltage gain?

When cascading amplifier stages, such as in a multi-stage active filter, how is the overall transfer function determined from the individual stage transfer functions?

An op-amp is used in the circuit of Figure 13.23 (gain = 4) and is powered by plus/minus 15 V supplies. The input is vs(t) = 2.5 sin(100,000 * pi * t). The op-amp has a slew rate of 0.5 V/microsecond. What is the approximate shape of the output waveform?

Which statement best describes the difference in input impedance between an inverting and a non-inverting ideal op-amp amplifier?

For a first-order Butterworth filter (n=1), what is the roll-off rate of the transfer function magnitude for frequencies much greater than the cutoff frequency fB?

What is the output impedance of an ideal non-inverting amplifier circuit?

In a real op-amp, where is the open-loop gain magnitude typically highest?