John Lehman

John Lehman
John Lehman is Engineering Manager for Dataforth Corp., Tucson, AZ. He can be reached at [email protected].

Stories by John Lehman

Why Use Isolated Signal Conditioners? Part 2: DC and AC Common-Mode Rejection and Measurement Range and Input Protection

Isolating power sources and sensor signals is the most effective method for eliminating undesirable ground loop currents and induced electrical noise when collecting data using PC-based DA equipment. This article provides an understanding of how measurement inputs become corrupted and why it is important to isolate them. The second part of this two-part article deals with more of the most common roadblocks to successful measurements: DC and AC common-mode rejection and measurement range and input protection.

Why Use Isolated Signal Conditioners? Part 1: Crosstalk and Common-Mode Voltage

Isolating power sources and sensor signals is the most effective method for eliminating undesirable ground loop currents and induced electrical noise when collecting data using PC-based DA equipment. This article will provide an understanding of how measurement inputs become corrupted and why it is important to isolate them. The first part of this two-part article deals with two of the most common roadblocks to successful measurements: crosstalk and common-mode voltage.