E7G11
PRACTICAL CIRCUITS · Operational amplifiers: characteristics and applications
E7G11E7G →
What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3,300 ohms and RF is 47 kilohms?
- A28
- B14
- C7
- D0.07
Why Figure E7-3 is a standard inverting op-amp stage, where the absolute (magnitude) voltage gain is simply the ratio of the feedback resistor to the input resistor, RF/R1. Here 47,000 divided by 3,300 gives about 14.2, so the gain rounds to 14. The minus sign that indicates the 180-degree phase inversion is dropped because the question asks for absolute gain.
Watch out The choice of 28 comes from doubling the ratio, and 0.07 is the reciprocal R1/RF, which would be an attenuator rather than an amplifier.
Inverting op-amp: gain = RF over R1, feedback on top. Divide, don't multiply.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
The rest of E7G
- E7G01 What is the typical output impedance of an op-amp?
- E7G02 What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor?
- E7G03 What is the typical input impedance of an op-amp?
- E7G04 What is meant by the term "op-amp input offset voltage"?
- E7G05 How can unwanted ringing and audio instability be prevented in an op-amp audio filter?
- E7G06 What is the gain-bandwidth of an operational amplifier?
- E7G07 What voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?
- E7G08 How does the gain of an ideal operational amplifier vary with frequency?
- E7G09 What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1,000 ohms, RF is 10,000 ohms, a…
- E7G10 What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1,800 ohms and RF is 68…
- E7G11 What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3,300 ohms and RF is 47…
- E7G12 What is an operational amplifier?