If the circuit load resistor is varied within design limits, the circuit voltage gain remains the same.

If the circuit load resistor is varied within design limits, the circuit voltage gain remains the same.

• A. increases
• B. remains the same
• C. decreases
• D. becomes unpredictable

Answer: (B)

In a negative-feedback op-amp circuit, the voltage gain is set by the feedback network—the ratio of the resistors in the feedback path—rather than by what the load does at the output. The op-amp adjusts its output so that the voltage at the inverting input matches the input voltage, enforcing a fixed relationship between input and output determined by that resistor ratio. The load simply draws current from the output; as long as the load is within the amplifier’s ability to drive (no excessive current, no saturation or output impedance effects beyond design limits), the feedback keeps the same output voltage ratio, so the gain stays constant. If the load were to demand more current than the device can supply, you’d see a change due to output limitations, but within design limits the gain remains the same.

In a negative-feedback op-amp circuit, the voltage gain is set by the feedback network—the ratio of the resistors in the feedback path—rather than by what the load does at the output. The op-amp adjusts its output so that the voltage at the inverting input matches the input voltage, enforcing a fixed relationship between input and output determined by that resistor ratio. The load simply draws current from the output; as long as the load is within the amplifier’s ability to drive (no excessive current, no saturation or output impedance effects beyond design limits), the feedback keeps the same output voltage ratio, so the gain stays constant. If the load were to demand more current than the device can supply, you’d see a change due to output limitations, but within design limits the gain remains the same.