A New Simple Wide-Band Current-Measuring Device

The current conveyor¿a new circuit building block recently introduced¿is applied to the design of a simple current-measuring probe. The monopolar version of this probe features high stability and accuracy (0.5 percent of nominal reading). A dc to 100-MHz frequency band is obtained from the bipolar version. Both versions minimize the disturbance to the measured circuit by presenting a very low impedance at the current-measuring terminals. The output voltage of the probe is directly proportional to the measured current with the transimpedance being chosen almost at will. The design makes use of a dual transistor and a commercially available integrated circuit.