3. The amplifier shown in Figure 3-1 is used in the design of a pre-amplifier in a scanning tunnelling microscope (STM). It converts the input current, which is a measure for the height of a conducting sample, into a voltage that can be further processed to construct a 3D-image of a surface. It is constructed with an uncompensated operational amplifier having the open loop gain response shown in Figure 3-2. The amplifier has R1 = 5 kQ2, Ry= 1 kQ2, and C = 200 nF. R Figure 3-1. 140 - 120- 100 Magnitude in decibels -120- 10m 100m 1 10 IK ICK 100K IM 10M 100M Frequency in Hz Figure 3-2