This negative ion generator is a high voltage generator circuit that use a 555 timer circuit to generate square-wave pulses . The square wave pulses are applied to the Q1 transistor ( Tip120 ) that provide enough current to the Q2 ( 2N3055 ) transistor to turn it on .
Each time when the Q2 transistor is turned on current flows through the high voltage auto-transformer, T2 ,to the a 10 kilovolt high voltage diode (D1 IMD5210). The polarity of the D1 IMD5210 diode is biased to place a negative charge on C3 and C4, leaving the discharge point negatively charged.
Voltage from the discharge point negatively charges the air forced past it by the fan.
The output of the T1 transformer must provide 12 volts . Be careful if you want to construct this project , may be dangerous .