1) Radio electronic 
The Neutrodyne was a particular type of tuned radio frequency (TRF) radio receiver, in which the instability-causing inter-electrode capacitance of the triode RF tubes is cancelled out or `neutralized`. to prevent parasitic oscillations which caused `squealing` or `howling` noises in the speakers of early radio sets. In most designs, a small...
circuit element inserted in an amplifier to provide neutralization