A microphone preamplifier stage uses an ideal operational amplifier (infinite…
PHYSICS · Multi-part · Fermi University Physics · Electronics, Instrumentation & Communication · Feedback, operational amplifiers and analogue signal processing · Feedback, operational amplifiers and analogue signal processing
Electronics for Measurement, Ch The operational amplifier and negative feedback
Problem
A microphone preamplifier stage uses an ideal operational amplifier (infinite open-loop gain, no input current) with a feedback resistor Rf=120kΩ and an input resistor R1=15kΩ.
((a)) Find the gain if the signal is applied through R1 to the inverting input, with the non-inverting input grounded.
((b)) Find the gain if the same two resistors are instead wired as a non-inverting stage (signal at the non-inverting input, R1 from the inverting input to ground, Rf from the inverting input to the output).