I was just on the phone explaining to a young engineer how to do an error budget analysis on some fairly simple circuits. Later, I mentioned this while I was visiting my friend Martin, and he said he had been quite surprised when he found that many engineers in Europe were quite unfamiliar with the concept of an error budget. How can you design a good circuit without being aware of which components will hurt your accuracy?

When I was a kid engineer back in 1962, my boss George Philbrick gave me a book on differential amplifiers by Dr. R. David Middlebrook, and he asked me to do a book review. I studied the book, and it was full of hundreds of partial differential equations. If you wanted the output of a circuit with fourteen components, you could see a complete analysis of how each component would affect the output offset and gain. Each equation filled up a whole page. It did this several times.

Yet the book didn't offer any insights into what's important. I mean, is ( ? d( R1) more important than R1 d( ?)? In retrospect, I'm glad I didn't submit any critique...