Digitally Switched Voltage Controlled Current Sources for Application in Hysteresisgraph of Low Magnetizing Fields

The paper presents the design and construction of the digitally switched system of the voltage controlled bipolar current sources. The developed current sources are modified version of the classic Howland current pump adjusted to deliver sinusoidal current waveform of amplitude 1–10 mA and 10–100 mA. The voltage input and current output are switched between developed current sources with the digital 2-channel switch controlled with LPC1115 microcontroller. The developed device can be applied in the hysteresisgraph for investigation of soft ferromagnetic materials in low magnetizing fields region known as the Rayleigh region. The SPICE simulations and results obtained with the developed device indicate that it works correctly and allows to investigate even very soft ferromagnetic amorphous alloys in low magnetizing fields.