Hi

Please have a look on the attachment. Please help me with it. Thanks a lot.

Regards
PG

 

Q1: The voltage ACROSS D1 and D2, i.e. from cathode of D1 to cathode of D2

ii: because it's typically in the mV range
i: because the inverting input is clamped to the output via the diodes, which have 5.4V voltage drop across them at most
iii: remember that the Opamp will move it's output voltage trying to make both inputs equal? The 5.4V across the diodes will also appear over R1, if you want the same voltage drop across diodes and R1, therefore having zero voltage difference between (+) and (-) inputs

iv: because it's in general an input having a very high impedance, nA to uA.

 

Thank you for the help.

Regards
PG