Chapter 1. The Op Amp's Place in the World
1.1. The Problem
In 1934, Harry Black [1
] commuted from his home in New York City to work at Bell Labs in New Jersey by way of a railroad and a ferry. The ferry ride relaxed Harry, enabling him to do some conceptual thinking. Harry had a tough problem to solve; when phone lines were extended long distances, they needed amplifiers, and undependable amplifiers limited phone service. First, initial tolerances on the gain were poor, but that problem was quickly solved with an adjustment. Second, even when an amplifier was adjusted correctly at the factory, the gain drifted so much during field operation that the volume was too low or the incoming speech was distorted.
Many attempts had been made ...