What is a current probe

What is a current probe?

• The current probe shall have a specified transfer impedance over a specified frequency range, i.e. a specified ratio of the RF voltage induced in the probe to the known RF current in a single wire passing through the probe when measured according to a specified procedure.
• The insertion impedance (insertion loss) of the current probe lead EUT shall be less than 1Ω over the specified frequency range.
• The current probe should be constructed in such a way that the effect of the electric field on the measurement results is negligible.
• In order to realize the specified test arrangement, the current probe shall be provided with a specified connection port (connector) for connection to standard measuring equipment. In addition, the input impedance of the measuring equipment to be connected to the current probe shall be specified.
• The maximum rating for unsaturated currents should be included in the specifications for current probes Current probes should be calibrated in accordance with specified procedures.

Type:

Current probes are divided into:

• Monitoring Current Probe (used as EMI test common mode current)
• Injection Current Probe (used as BCI injection for common-mode interference currents)

Role:

Current probes or current transformers can measure Class III nuisance currents on power, signal, and load wires, etc. The card-type structure of the probes is easy to use.

Regardless of the number of wires, the common mode current on a wire can be measured by simply jamming the current probe around the wire. In this case, the differential mode currents in the wire induce signals of equal amplitude but opposite direction, with the result that these signals cancel each other out to a large extent. This allows for the measurement of small common mode currents in the presence of large amplitude differential mode (operating) currents in the conductor.

Current probes in line with the standard provisions of the current probe see GB/T6113.102-2008.