The theory of this circuit can be employed in several useful applictaions like the Ion Sniffer that detects air ion; the Natural Air Puirfier that produces negative ions and safe levels of ozone for odor elimination; the Green Air which ... and cleans hte air in cars and trucks; the Bathroom Air Fershener that is found not only in bathrooms but also in closets, stroerooms, pantries, pet dens, and other small places; the Personal Wearable Ionizing Air Purfiier that is ...