An amplifier normally has a huge gain which outputs the input voltage Vin to an output Vout. If gain is G then Vout = G*Vin.
But what about in case of a data-acquisition board's amplifier?
Imagine we apply lets say a 5V DC signal to a single-ended data-acquisition board's channel. So in this case Vin is 5V and we expect Vout to be 5V as well. So what is the gain of this amplifier here?
And if the gain is 1 for a data-acquisition amplifier why an amplifier is always needed before sampling the voltage by ADC?
Answer
I don't know the specifics of your data board, but in general an amplifier with a gain of 1 (aka unity gain) is useful for its other properties:
- high input impedance
- low output impedance
These make it a good buffer between various stages so that they don't load each other.
And buffer amplifiers are used as the first stage of data acquisition boards for this reason.
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