Drift Self-compensating Type Flux-meter for Automatic Magnetic Flux Measurement

In magnetic flux measurement, output voltage drift of electronic integrator is an essential problem. In this work, we have developed a new kind of Miller type integrator using a sample and hold amplifier. Input bias current was measured and this value was hold in the sample and hold amplifier, after that input bias current of Miller integrator was compensated automatically using the value which holds in the sample and hold amplifier. Developed flux-meter shows the drift of flux-meter are smaller than 10$^-5$ Wb/min in full scale of 10$^-2$, and we could also measure multi-channel magnetic flux simultaneously.