Anticipator circuit speeds signal settling to a final value

摘要

The circuit in this Design Idea anticipates, or jumps instantly to, the final voltage of an input-signal change. It relies on the fact that the intended input signal changes exponentially with a known time constant. This circuit was adapted from a 1970s-era instant-reading electronic thermometer, which displayed a patient's body temperature within seconds after a thermometer probe was placed under the patient's tongue. It exploits the fact that the temperature probe's exponential thermal response-time characteristic is known.