应用笔记 4518

Circuit Transfers Resistance Value Through Isolation Barrier

By: Leo Sahlsten

摘要 : This circuit monitors a resistance value in a noisy or otherwise hostile environment. Connected across the secondary winding of an isolation transformer, the unknown resistance reflects to the primary where it forms a voltage divider with a 2.2kΩ resistor. The divider produces a reduced-amplitude clock signal that is capacitively coupled, rectified, and filtered to produce a dc output voltage corresponding to the monitored resistance.