A simple simulation adapted from the [YouTube video](https://youtu.be/F9w5r5l0J8Y) by devttys0.
The problem is to invert a 0-20v signal using only an opamp powered by a +/-15V DC supply. The circuit can be broken down to three stages:
1. Shifting the signal down to be +/-10V signal > Add a 0.1uF cap which will block any DC element in the signal.
2. Inverting the signal > Use a classic inverting a...