E7G10
PRACTICAL CIRCUITS · Operational amplifiers: characteristics and applications
E7G10E7G →
What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1,800 ohms and RF is 68 kilohms?
- A1
- B0.03
- C38
- D76
Why Figure E7-3 is the standard inverting op-amp stage, whose absolute (magnitude) voltage gain is simply RF divided by R1. Here 68,000 ohms divided by 1,800 ohms equals 37.8, which rounds to about 38. The minus sign that indicates phase inversion is dropped because the question asks for absolute gain.
Watch out The choice of 76 is what you get by doubling the answer, and 0.03 is R1/RF, the ratio inverted; remember the feedback resistor goes on top of the fraction.
Gain = RF/R1, feedback over input. Big feedback resistor means big gain.
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?