Magnetostrictive transducers for compressive force using ferrite

A transducer for compressive force using Mn-Mg and Ni-Zn ferrite is offered in this paper, based on the magnetomechanical effect that the magnetic characteristics of the material are influenced by mechanical stress. They can be realized by applying a Royer's and Marzolf's circuit. The input to the transducer is pressure, and the output is an oscillator frequency. The change of the magnetic characteristics caused by repeated application and removal of 1.8 kg/mm
²
pressure can be reversible. With a Marzolf type transducer, at low pressure the input-output characteristic shows a hysteresis till 0.9 kg/mm
²
, but at higher pressure than 0.9 kg/mm
²
the characteristics are completely linear. With a Royer type transducer the characteristics are almost linear, although a little hysteresis is found over the range from 0 to 1.8 kg/mm
²
. The experimental results show that at low pressure the characteristics are nonlinear, including the hysteresis, and the influence of the temperature is 1.2%/°C over the range from 18 to 30°C. The method is also useful in the case of investigating the flux reversal mechanism under various stress conditions.