Hi Everyone!
I have this basic differential amplifier, it amplifies the voltage over R7 by 100 and the sim works fine. However if I connect V2(-) to V1(-) then it doesn't work, the output of U1 becomes basically zero. So I would like to know why? I think it's my lack of fundamental understanding of LTSpice and/or differential amplifiers that is the problem. And if I can't connect V2(-) to V1(-) and I wanted to do something useful with the U1 output e.g. connect it to the circuit made up of V1/R7/R6 then I would have to use a e.g. optocoupler,? That can't be so..
I have this basic differential amplifier, it amplifies the voltage over R7 by 100 and the sim works fine. However if I connect V2(-) to V1(-) then it doesn't work, the output of U1 becomes basically zero. So I would like to know why? I think it's my lack of fundamental understanding of LTSpice and/or differential amplifiers that is the problem. And if I can't connect V2(-) to V1(-) and I wanted to do something useful with the U1 output e.g. connect it to the circuit made up of V1/R7/R6 then I would have to use a e.g. optocoupler,? That can't be so..