5. Open-loop current transducer associated with a transformer

• Principle

In the case of the flux-compensated transducer, we have noted the limitations induced by the need to control a significant secondary current over a wide frequency range. To overcome this limitation, it is possible to combine the principles of open-loop measurement and the current transformer. In this way, the output voltage of the Hall generator is added to the output voltage of the transformer. Figure 13 shows the schematic diagram and its equivalent model. The resistor R ₃ placed at the end of the connecting cable adapts the cable impedance at high frequencies. Indeed, at 100 MHz a 1 m coaxial cable corresponds to half a wavelength (considering...