voltageonly

Voltageonly is a concept used in electronics and instrumentation to describe systems, measurements, or control schemes that rely primarily on voltage information while not directly measuring current. In voltage-only approaches, current may be neglected, assumed constant, or inferred from a known impedance, rather than sampled directly. The term is not a formal standard in all contexts but is used in discussions contrasting voltage-based sensing with current-based sensing.

In sensing applications, voltage-only devices detect changes in potential with high-impedance instrumentation, such as voltage dividers, buffer amplifiers, or capacitive non-contact voltage detectors. The absence of a direct current measurement can simplify hardware and reduce loading on the measured circuit. In power electronics, voltage-only control refers to schemes where output voltage is the feedback signal for regulation, while current sensing is used only for protection or fault detection.

Advantages of voltage-only designs include reduced component count, lower power draw, and minimal disturbance to the circuit under test. Limitations include the inability to measure or infer instantaneous power directly, sensitivity to source impedance and loading, and potential safety concerns if high-impedance sensing causes unnoticed current surges.

Related concepts include voltage sensing, current sensing, impedance, and voltage-mode control. Voltageonly is thus best applied when voltage information suffices for monitoring, control, or signaling and where current information would add unnecessary complexity or cost.