I made a two-stage amplifier operational amplifier, the instrument amplifier used in the first stage, amplified 50 times the ordinary amplifier used in the second stage, amplified 30 times, how to accurately measure the respective amplification factors of the two amplifiers. At present, if the AC input is read with an oscilloscope, the respective error is 10%, and the DC error is about 0.2%. The resistors used in the amplifier are all precision of a few ten thousandths. It is impossible to have such a large error in the AC?
Darren 发表于 July 23, 2020
For AC signal amplification, we must also pay attention to the filtering effect caused by bandwidth and capacitance.
Helen 发表于 July 23, 2020
My frequency is only 1KHZ, and the capacitor was removed by me during the single-stage test.
Tony 发表于 July 23, 2020
Since the gain of the DC signal is accurate
That can only consider the problem of inconsistent gain caused by the signal bandwidth
Including the gain bandwidth product of the amplifier
