What term describes a condition of balance in a device or system that results in zero output?

The term that describes a condition of balance in a device or system that results in zero output is "null-balance." In many measuring instruments and systems, including electrical and mechanical devices, achieving a null-balance means that the inputs or variables have been balanced out so that there is no net output or signal. This condition is often essential for calibration, allowing the system to measure deviations from this point without interference from other variables.

For instance, in a null-balance condition, any applied input results in equal and opposite responses, thereby bringing the display or output to zero. This is critical in measurement systems like strain gauges or in bridge circuits, where precise balance indicates that measurements can be trusted to reflect true physical changes without additional noise or error.

This term is foundational in understanding how various systems achieve accurate measurements or observations by establishing a baseline where no signal is present.