Dear Dennis... EN-Genius Network's Dennis Feucht answers your design queries in his new Circuit Design Clinic! September, 2011

EN-Genius Network presents a new, interactive analog design service to readers! Send us your design questions (with relevant data; schematics in JPEG or GIF, please) for some free engineering advice from EN-Genius Network's circuit consultant, Dennis Feucht, on how you might solve a design problem or improve circuit performance. Submissions may be edited for clarity or brevity, and submitters and their email addresses will remain anonymous (unless otherwise indicated). Please send your questions to Dennis here.

In the Depths of Circuit Refinement

by Dennis L Feucht

This is an account of how a modified dual-slope DVM with a ±4 V input range and a full-scale (fs) count of 12500 (or about 13.3 bits) with a μC-driven 4-digit display was refined. In telling the tale, some of the subtleties of the last 5% of the circuit design are manifested. Final refinements can take far more than 5% of the total design time in that as the end is approached, the problems become more subtle and difficult.

...download complete article here (385 KB PDF)