The Operational Amplifier

What are the two fundamental rules for analyzing circuits with an 'ideal' op amp?

For an ideal inverting amplifier as shown in Fig. 6.3, if vin = 5 sin(3t) mV, R1 = 4.7 kOhms, and Rf = 47 kOhms, what is the output voltage vout?

In a noninverting amplifier circuit as shown in Fig. 6.6a, with vin = 5 sin(3t) mV, R1 = 4.7 kOhms, and Rf = 47 kOhms, what is the output waveform vout?

What is the primary purpose of a voltage follower circuit?

For the summing amplifier in Fig. 6.9, if R = Rf and it has three inputs v1, v2, and v3, what is the expression for the output voltage vout?

What is the output voltage vout for the difference amplifier shown in Fig. 6.10, assuming all four resistors are equal (R)?

In the two-stage op amp circuit of Fig. 6.15, what is the overall input-output relationship for vout in terms of v1 and v2?

What is the primary characteristic of a Zener diode that makes it useful for creating a reference voltage?

In the op amp-based current source of Fig. 6.21a, what determines the current Is flowing through the load resistor RL?

According to Table 6.3, what is the typical open-loop gain A for a uA741 op amp?

What is the key difference between 'open-loop voltage gain' and 'closed-loop voltage gain' for an op amp?

What is the effect of negative feedback in an op amp circuit?

What is the phenomenon known as 'saturation' in a practical op amp?

What is the 'slew rate' of an op amp?

According to Table 6.3, what is the slew rate for an LF411 op amp?

How does a comparator circuit typically use an op amp?

What is the main function of an instrumentation amplifier as described in Section 6.6?

In the Practical Application example of a fiber optic intercom, a microphone outputs a peak of 40 mV and the LED requires 1.6 V. If R1 is chosen as 1 kOhm in the noninverting amplifier, what value is required for Rf?

What does the term 'CMRR' stand for, and what does a high value indicate?

According to Table 6.3, what is the typical input resistance for an LF411 JFET input op amp?

What is 'input offset voltage' in a practical op amp?

In the fuel tank monitoring circuit of Example 6.3, a summing stage with four equal 1 kOhm resistors (R1-R4) produces an output vx = -(v1 + v2 + v3). If the full condition output from this stage is -8.8 V and the final desired output is 1 V, what must be the gain (R6/R5) of the following inverting stage?

What is the primary reason that nodal analysis is generally preferred over mesh analysis for op amp circuits?

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

The output of a practical op amp is limited to a range of approximately -5V to +9V. What does this imply about its DC power supplies?

An inverting amplifier is built with R1 = 100 ohms and Rf = 400 ohms, using a DC input of 2.5V. What is the output voltage, vout?

In the detailed op amp model shown in Fig. 6.24, what do the parameters A, Ri, and Ro represent?

Why might a designer choose an LF411 op amp over a uA741 for a circuit that must handle fast-changing signals?

For an ideal instrumentation amplifier with R4/R3 = R2/R1 = K, what is the output voltage vout?

What is the consequence of the first ideal op amp rule, 'No current ever flows into either input terminal,' on the analysis of an inverting amplifier?

What is the purpose of the 'offset null' or 'balance' pins on most op amps?

If a summing amplifier has three inputs v1, v2, v3, with corresponding input resistors R, R, and 2R, and a feedback resistor Rf = 4R, what is the output voltage vout?

What is a 'virtual ground' in the context of an op amp circuit?

A comparator circuit has a 2.5V reference voltage connected to its non-inverting input. If the op amp is powered by +/- 12V supplies, what is the approximate output voltage when the signal at the inverting input is 3.0V?

What are the ideal values for input resistance (Ri) and output resistance (Ro) for an ideal op amp?

An op-amp circuit is designed to have a closed-loop gain of -10. If the op amp saturates at +/-14V, what is the approximate range of input voltages for which the amplifier will operate linearly (without saturating)?

In the design of a reliable voltage source using a Zener diode and an op amp (Fig. 6.20), what is the main advantage of using the op amp over a simple Zener circuit?

Which of the following op amp types listed in Table 6.3 would be most suitable for an application requiring the lowest possible input bias current, such as measuring a signal from a very high impedance source?

For a noninverting amplifier with R1 = 1 kOhm and a desired gain of 40, what value is required for the feedback resistor Rf?

What is the key structural difference between an inverting amplifier and a noninverting amplifier?

A uA741 op amp with a slew rate of 0.5 V/us is required to change its output from -5V to +5V. What is the minimum time this output swing will take?

An op amp has a differential gain A of 100,000 and a common-mode gain ACM of 0.5. What is its common-mode rejection ratio (CMRR) in dB?

What is the historical significance of the Philbrick K2-W device mentioned in Section 6.1?

If a difference amplifier has v1 = 2 + 3sin(3t) volts and v2 = 2 volts, what is the expected ideal output?

In designing a current source to deliver 500 uA to a resistive load using the circuit topology of Fig. 6.23, a 9V battery and 1N750 Zener diode are used to create a reference voltage. If the diode voltage is approximately 4.9V, what should the value of the reference resistor Rref be?

An inverting op-amp circuit has R1 = 2 kOhm and Rf = 20 kOhm. What is its closed-loop gain?

A noninverting op-amp circuit has R1 = 5 kOhm and Rf = 45 kOhm. What is its closed-loop gain?

For the comparator circuit in Example 6.8, designed to output 5V if the signal is below 3V and 0V otherwise, what type of power supply configuration is used?

When analyzing a cascaded op-amp circuit, how is the input to the second stage determined?

In the context of the ideal op amp model, which of the two primary analysis techniques, nodal or mesh, is almost universally preferred and why?