Operational Amplifiers - Technical MCQs

Q1:

fbq18_1007.gif The feedback resistor has a value of ______ in the given circuit

A 2 komega.gif

B 10.5 komega.gif

C 21 komega.gif

D 40 komega.gif

ANS:D - 40 komega.gif

This is a case of a Non-inverting amplifier
For the circuit of the fig, the voltage at the non inverting input is given by

Vo = V1(1 + Rf/R1)

630 = 30(1 + Rf/2)

Rf=40 kilo ohms