Instructions for the use of current probes: Be alert to the noise introduced by the ground wire

Current probe is a common tool for electrical measurement, but many users often ignore the noise problem introduced by its grounding method, which leads to distortion of measurement results.

When the current probe is connected to the reference ground through a long ground lead, a closed loop is formed. This loop acts like an antenna to couple electromagnetic interference in space, thereby superimposing high-frequency noise in the measurement signal. This noise may come from electromagnetic radiation generated by surrounding switching power supplies, radio waves, or other equipment, and is particularly significant in high-frequency measurements.

More insidiously, the ground loop also introduces ground noise. When there are multiple ground points in the system, the potential difference between the points will form a current through the ground loop, which will directly interfere with the measurement accuracy.

In order to avoid these problems, it is recommended to take the following measures: give priority to the use of the original grounding spring attachment of the probe instead of the long grounding wire to minimize the loop area; ensure that the measurement system is grounded at a single point to avoid the formation of a ground loop;