Abstract: Instrument apparatus and method for the cyclically concurrent display of the time related transitional characteristics of a plurality of samples, at least one of which may be a laboratory standard of known value, or all of which samples may be unknown. Separate electrical signals derived as the samples are simultaneously activated, exposed, treated, analyzed or observed are gated by multiplexing circuits on a split time basis that may allot equal or varied time periods for the separate samples. The strength of the signal from the samples may be separately or cooperatively adjusted to enhance comparison or differential features as the signals are delivered to display components for study or recording.

Abstract: A circuit and apparatus combination for maintaining a balanced or regulated operational condition in test apparatus that includes mechanical drive and sensor elements as the sensor is exposed to the changing conditions experienced in a test sample or a sampled environment. The circuit automatically drives mechanical elements of the system at a resonant frequency or at other prescribed conditions with voltage changes at an output section of the circuit being indicative of changes in the sample tested or in the sensors environment. Drive elements of the circuit are powered by a drive voltage to cause movement of the sensor and the changing power thus used is evaluated and cancelled out, while a separate input or response voltage that is derived from the resulting movement of the same drive elements is introduced to an Operational Transconductance Amplifier together with an input control current likewise derived from such response voltage.