Abstract
Measuring a small change of low impedance at high frequency is more valuable in industry than measuring an absolute impedance. This paper presents an electronic circuit that is capable of measuring a small change of low impedance of comparatively high loss materials as well as its absolute impedance at 3MHz. This circuit may find a wide range of applications in industrial operations or in agricultual and medical fields. The most important qualities required for this type of instrument are its sensitivity for loss and reactance, and stability during a continuous operation for long hours. The sensitivity and stability of this new circuit are satisfactory. Using this instrument as capacitance and loss meter, observed stability was within less than ±1μA (ΔC2=1.4×10-3pF) and ±0.5μA (ΔR2r/R2r=0.029%) respectively in terms of zero drift during a 10 hours continuous operation.
