1.Why the amplifier will be consuming more current than normal and self-heating when it rail out?as is saying in《Properly terminating an unused op amp》Fig.2(a)
"The circuit in Fig. 2a connects both inputs together and to GND, but it ignores the effects of input offset voltage (VIO) between the inputs. Depending on the polarity of VIO, the small voltage between the inputs causes the output to drive to one supply rail or the other. Since this circuit has large open loop gain, the output saturates and the device consumes extra current. This implementation should be avoided."
if the ampilfier is of JFET-input, its input current is as low as nA, and output current is 0A, why the OP can consume much current, and where is the current loop?