barkhausen Definition

In electronics, Barkhausen criterion is a condition for sustained oscillations in an electronic oscillator. It states that for sustained oscillations, the phase shift around the loop must be an integer multiple of 2π radians in phase and the gain must be equal to 1 (or more accurately, the magnitude must be equal to 1 with a phase shift that is a multiple of 2π). This term is sometimes used to refer to the phenomenon in a ferromagnetic material where domains start to change direction when a certain magnetic field is applied, which is also called Barkhausen effect.