Figure $18

Question

Figure $18 < 1$
-The input impedance of the amplifier in Figure 18-1(b)is ________.

Quizplus · Accepted Answer

The input impedance of the amplifier in Figure 18-1(b) is very high because it is determined by the input resistor (R1) and the large open-loop gain of the op-amp. In this circuit, R1 = 100 kΩ and the open-loop gain of the op-amp is very high (ideally, infinite). Therefore, the input impedance is effectively infinite, and the voltage at the inverting input is essentially identical to the voltage at the non-inverting input.

Figure 18<118 < 118<1 -The Input Impedance of the Amplifier in Figure 18-1(b)is ________

Figure $18 < 1$ -The Input Impedance of the Amplifier in Figure 18-1(b)is ________