By means of the current limiting resistor 424 and the diode 425 for half wave rectification, the oscillating signal is limited to positive half wave for biasing the base of the transistor 422 and creating {HEAD ~ a current ice} for heating {TAIL ~ the heating mechanism} 41 
for heating
By means of the current limiting resistor 424 and the diode 425 for half wave rectification , the oscillating signal is limited to positive half wave for biasing the base of the transistor 422 and creating { HEAD ~ a current ice } for heating { TAIL ~ the heating mechanism } 41
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