Finding gain with inverting amplifier


Joined Feb 12, 2009
The section of the circuit from A to B is an attenuator (or voltage divider). It therefore has a gain of LESS than 1.

The section of the circuit from B to D is an inverting amplifier. It will have a gain of MINUS(something).

As this is the homework section, I will leave it to you to find out the formulas to work out the actual values.

Note that point C is a "virtual earth" and has a potential very close to earth at all times. Therefore R1 is in parallel with Rb and this must be taken into account when calculation the gain of the attenuator section.

The gain of the total circuit (from A to D) is the product of the gain of both sections. Gain(A-B) x Gain(B-D).