How an op amp works: if the positive input is higher than the negative input, then the output will (very quickly) increase (until it reaches close to the positive power voltage). if the negative input is higher than the positive input, then the output will decrease (until it reaches close to the negative power voltage). If the two inputs are the same, then the output will not change.
If a circuit has a negative feedback resistor, then increasing the output value will increase the value at the negative input, so it can reach a point where it is the same as the positive input, so the output stops moving. This is what "the op-amp will do whatever it can to keep both inputs the same" means - the op amp is just changing the output up or down, but because of the negative feedback resistor, the inputs might end up the same, so the output can stop moving. If the output reaches the positive or negative power voltage, it can't move any more (so the inputs will not match).
If a circuit has a negative feedback resistor, then increasing the output value will increase the value at the negative input, so it can reach a point where it is the same as the positive input, so the output stops moving. This is what "the op-amp will do whatever it can to keep both inputs the same" means - the op amp is just changing the output up or down, but because of the negative feedback resistor, the inputs might end up the same, so the output can stop moving. If the output reaches the positive or negative power voltage, it can't move any more (so the inputs will not match).
Statistics: Posted by nigel — Sun Sep 29, 2024 8:16 pm
