The small voltage that must be applied between an op amp's inputs to bring its output to zero, caused by mismatch among internal devices. It is multiplied by the circuit's gain into an output error: 2 mV at a gain of 100 shifts the output by up to 200 mV.
Japanese name: 入力オフセット電圧
Input offset voltage appears in 2 practice questions across 2 topics, including Analog and electronic circuits, How to read datasheets.
Field: How to read datasheets
Answer: A. The small voltage that must be applied between the inputs to correct for the output not being 0 when the inputs are equal
Tiny mismatches in a real op-amp's input transistors mean the output is not zero even with both inputs at the same voltage. Referred to the input, this is the input offset voltage: a few mV in general-purpose parts and tens of µV or less in precision parts. It appears at the output multiplied by (1 + Rf/Ri) and drifts with temperature. For high-gain DC work with tiny signals such as thermocouples, low-offset or chopper-stabilized op-amps are used.
Answer: B. 200 mV
Input offset voltage behaves like a small voltage source in series with the input and appears at the output multiplied by the non-inverting amplifier's gain (1 + Rf/Ri). 2 mV × 100 = 200 mV, which is a 4% error against a 5 V full scale, for example. Estimate with the max value rather than the typ value, and also add the change due to temperature drift (µV/°C). For precision measurement, choose a zero-drift (chopper) type with an offset of a few µV, or calibrate in software. 2 mV is the value obtained by forgetting to multiply by the gain.
Referred to the input, this is the input offset voltage: a few mV in general-purpose parts and tens of µV or less in precision parts.
Which correctly describes the input offset voltage of an op…Input offset voltage behaves like a small voltage source in series with the input and appears at the output multiplied by the non-inverting amplifier's gain (1 + Rf/Ri).
A non-inverting amplifier with a gain of 100 is built using…As an Amazon Associate I earn from qualifying purchases.
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