This question came up in my exam and is goes like this:
The two following montages were dimensioned to work as signal amplifiers but none of them works correctly.
Explain why and say what signal we get on the output when the input is a sinusoidal signal with 20 mV of amplitude.
The first one seems like an subtractor but i have no ideia why its wrong
About the second one it has positive feedback so i think it can only be a comparator and never an amplifier.
Usually the expression for the second one is something like Vi=-R2/R1*V1 but since we have a resistor on the non inverting input it messes up the things a little bit..
Also is seems more like a subtractor circuit but it can not be so since it has positive feedback....
Thanks
The two following montages were dimensioned to work as signal amplifiers but none of them works correctly.
Explain why and say what signal we get on the output when the input is a sinusoidal signal with 20 mV of amplitude.
The first one seems like an subtractor but i have no ideia why its wrong
About the second one it has positive feedback so i think it can only be a comparator and never an amplifier.
Usually the expression for the second one is something like Vi=-R2/R1*V1 but since we have a resistor on the non inverting input it messes up the things a little bit..
Also is seems more like a subtractor circuit but it can not be so since it has positive feedback....
Thanks
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