Circuit simulations ... arise because the op amp isn’t really perfect. A real op amp would not hit the 15V rail exactly. It will get close depending on how much current you draw from the output.

Operational amplifiers (op amps) can be used to create (1) precision current sources and sinks, which range from submicroamps to milliamps, and (2) current regulators, which range from milliamps to ...

Current-feedback operational amplifiers are devices where the main feedback path from output to input carries a current, and not a voltage, as in voltage feedback op-amps. Current-feedback op-amps do ...