The small current at the input of an op amp is called

The small current at the input of an op amp is called

• A. Input bias current
• B. Input impedance
• C. Output current
• D. Slew rate

Answer: (A)

The small current that flows into or out of the op-amp’s input pins to bias the internal transistors is called the input bias current. Real op-amps aren’t ideal: their inputs draw a tiny DC current even with no signal, because the input transistors require some bias to operate. This is what the term describes. This is distinct from input impedance, which is the effective resistance the source sees at the input (usually very high for most op-amps, but it’s about resistance, not current itself). It’s also different from the output current, which is the current delivered at the output, and from the slew rate, which describes how quickly the output voltage can change in response to a step input. The exact size of the input bias current depends on the technology used: BJT-input op-amps typically have higher bias currents, while JFET- or CMOS-input devices exhibit much smaller bias currents.

The small current that flows into or out of the op-amp’s input pins to bias the internal transistors is called the input bias current. Real op-amps aren’t ideal: their inputs draw a tiny DC current even with no signal, because the input transistors require some bias to operate. This is what the term describes.

This is distinct from input impedance, which is the effective resistance the source sees at the input (usually very high for most op-amps, but it’s about resistance, not current itself). It’s also different from the output current, which is the current delivered at the output, and from the slew rate, which describes how quickly the output voltage can change in response to a step input.

The exact size of the input bias current depends on the technology used: BJT-input op-amps typically have higher bias currents, while JFET- or CMOS-input devices exhibit much smaller bias currents.