Power line noise refers to the effect of voltages and currents at power line frequency (typically 50 Hz or 60 Hz) on electronic measuring instruments. It is caused by electromagnetic fields and coupling from live wires in the residential or public power grid and superimposes on the actual useful signal, particularly for small measured quantities.
Significance for Measurement Technology
In measurement technology, power line hum is a typical source of interference that can lead to distorted measurement values, increased noise, or periodic superimposed signals. Particularly sensitive measurements—such as those in the µV range or involving high-resolution sensor signals—are significantly affected by these 50/60-Hz disturbances. For this reason, high-quality measuring instruments employ specific measures such as filtering, differential inputs, proper grounding, and shielding.
Suppression in Delphin measuring instruments
In Delphin measurement and data acquisition systems, such as the devices in the Expert and Message series, power supply hum is effectively suppressed by appropriate input filters and signal routing. As a result, even very small useful signals remain largely unaffected and can be recorded and evaluated with high accuracy. In practice, this is particularly important for long-term recordings, condition monitoring applications, or laboratory experiments in which low voltages or subtle signal changes must be reliably detected.