What is neutralization of a amplifier?

Answer 1

While there may be very rare exceptions to this, nearly 100% of the time neutralization of an HF PA or power amplifier vacuum tube has virtually nothing to do with VHF or UHF oscillations. VHF oscillations are almost always caused by a high impedance (parallel resonant) path from a grid to ground. The high impedance prevents the grid from being "clamped" or held at ground potential for RF at some frequency or range of frequencies. If this high impedance resonance happens to occur at a frequency range where the anode path to ground is parallel resonant, the tube can act like a tuned-plate tuned-grid oscillator. Hope this helps! It is also called Unilateralisation:- it is a process by which neutralising or nullifing the internal feedback effect causing internally, by connecting an additional network. It is explained breifly in the related link.