Precision thin film AC voltage divider

摘要

A precision AC input voltage divider on a substrate is printed as a serpentine pattern for a thin line of resistive material. Bothersome original "bad" stray capacitances to a ground, particularly those to or from the middle of the serpentine, are effectively removed by coupling to their ungrounded ends additional "good" stray capacitances that are themselves driven by the input voltage. The additional good stray capacitances are chosen to supply substantially the exact current needed by the original bad strays, so that the original resistive divider never "sees" the strays at all, and requires in addition only minimal conventional compensation by external parts. The additional good strays are obtained by a metallic conductor that is electrically connected to the input terminal, and runs adjacent to the serpentine resistance for part or all of its length.