抄録
An emitter current sensor was proposed in order to measure ion generation rates of corona discharge air ionizers aiming to investigate the effects of the operating condition on the neutralization performance. The emitter current is one of the most important operating conditions of a corona discharge air ionizer. A current sensor with high sensitivity is needed because the emitter current is small (nA or pA) and the voltage applied to the emitter is high (kilo volts). So, it is desirable to separate electrically the current detector from high voltage line. The proposed sensor consists of two areas: the high voltage region for detecting the emitter current, and the low voltage region for measuring the wave forms of the emitter current by using oscilloscope. The ion generation rates were obtained from the waveform of the difference between the total current and the displacement current. A MOSFET was used for detecting the emitter current, which enables to realize low cost measurement.
