2.98 A particular inverting amplifier with nominal gain of −100 V/V uses an imperfect op amp in conjunction with 100- kΩ and 10- MΩ resistors. The output voltage is found to be +1 V when measured with the input open and +0.5 V with the input grounded.
(a) What is the bias current of this amplifier? In what direction does it flow?
(b) Estimate the value of the input offset voltage.
(c) A 10- MΩ resistor is connected between the positive-input terminal and ground. With the input left floating (disconnected), the output dc voltage is measured to be −0.1 V. Estimate the input offset current.
(a) 100 nA into the amplifier; (b) −5 mV; (c) 10 nA