A power meter includes a sampling circuit configured to initially make electrical measurements of a unit under test at a first sampling frequency. The power meter includes an adaptive circuit. The power meter includes an accumulator configured to accumulate electrical measurements of the unit under test from the sampling circuit. After a change in sampling frequency from the first sampling frequency to a second sampling frequency, the sampling circuit makes second electrical measurements at the second sampling frequency. The adaptive circuit is configured to adjust the second electrical measurements from the sampling circuit according to a factor. The factor is based on a relationship between the first sampling frequency and the second sampling frequency. The adjustment yields adjusted second electrical measurements. The accumulator is further configured to accumulate the adjusted second electrical measurements.