This Norton Current OpAmp has a gain = 200 from the 100 ohm input to the collector output, provided the input doesn't saturate the ouput. Pin 5 output resistor and OpAmp + input resistor are low because it needs current to amplify. The two transistors, 2n3904's, are setup in standard ways. The diagram doesn't supply a "current opamp", so the read values are 0A, and it really amplifies current. DS
