Subelement D: Circuits— Topic 30: Op Amps
Question 3-30D3
Element 3 (GROL)Gain of a closed-loop op-amp circuit is determined by?
Explanation
The gain of a closed-loop operational amplifier (op-amp) circuit is precisely determined by the external components in its feedback network. Op-amps are designed with extremely high internal (open-loop) gain, which is often too high and unstable for practical applications. By implementing negative feedback using external resistors, capacitors, or other components, the overall circuit gain (closed-loop gain) becomes predictable, stable, and significantly lower than the open-loop gain. This external network allows engineers to set the desired amplification ratio for specific tasks, a fundamental concept in amplifier design.
Options A, C, and D are incorrect. Maximum operating frequency and load impedance (A) relate to the op-amp's performance limits and stability with a load, not the gain ratio itself. Supply voltage and slew rate (C) affect the maximum output swing and the rate at which the output can change, respectively, but do not directly determine the voltage gain. While op-amps have internal feedback networks (D) that contribute to their open-loop gain characteristics, it is the *external* feedback that shapes and defines the controlled, stable closed-loop gain.
Related Questions
3-30D1 What is the main advantage of using an op-amp audio filter over a passive LC audio filter?3-30D2 What are the characteristics of an inverting operational amplifier (op-amp) circuit?3-30D4 Where is the external feedback network connected to control the gain of a closed-loop op-amp circuit?3-30D5 Which of the following op-amp circuits is operated open-loop?3-30D6 In the op-amp oscillator circuit shown in Figure 3D6, what would be the most noticeable effect if the capacitance of C were suddenly doubled?