Aim-TTi IPROBER 520 Positional Current/Field Probe

The Aim I-prober 520 positional current probe is unlike any other current measurement device available. It is slim, good looking and very clever. Calibrated measurement of current normally requires the current to be passed through a closed magnetic loop. Typically this is done using some form of split clamp device. Whereas this is suitable for individual wires, it is of no use for measuring current in PCB tracks. The unique feature of the I-prober 520 is its ability to observe and measure currents flowing in PCB tracks by acting as a positional current probe. The magnitude of the signal is critically related to its position relative to the conductor which means that the probe tip must be positioned carefully. The size of the conductor (e.g. the width of a PCB track) also has a significant effect. This means that the sensitivity of the I-prober has to be adjusted to match the track width when quantitative measurements are required. A calibrator within the control box enables sensitivity adjustment in conjunction with a calibration graph. The measurement result will also include other field effects present at the tip of the probe and not just that coming from the current through the conductor. This may include DC effects from adjacent magnetised components and from the earth's magnetic field, plus AC effects from transformers and other field radiating sources. Current in adjacent tracks, or tracks on the opposite side of the PCB will also affect the measurement. There are potential solutions to these problems. The unwanted DC can be nulled out by observing the measurement without power to the circuit, whilst AC interference can be attenuated using bandwidth filters. The I-prober control box includes a wide range DC offset control and switchable filters.