Harold Black
1898 – 1983
Sketched negative feedback on a ferry-ride newspaper.
A Bell Labs engineer, Black conceived negative feedback in 1927 — reportedly sketching it on a newspaper during his ferry commute — trading raw gain for stability and low distortion. It is arguably the most important circuit idea of the century.
The op-amp tools here work because of Black's insight. His own patent office took nine years to believe it could work.
Portrait: a stylized blueprint-line rendering, not a photograph.
Contributions in the toolbox
- 1927
Negative feedback, sketched on a ferry-ride newspaper.
→ Op-Amp Gain