Question { 44537 }

what is Barkhausen Criterion?

Answer

Barkhausen's Criterion may be found in his book "Lehrbuch
der Elektronen-Röhren", 3. Band:, “Rückkopplung”, Verlag S.
Hirzel, 1935, Achte Auflage, pp. 4–5, 1960. He pointed out
that an oscillator may be described as an inverting
amplifier (a vacuum tube) with a linear frequency
determining feedback circuit. The non-linear amplifier is a
two-port with a static gain-factor equal to the ratio
between the signals at the ports. The linear feedback
circuit is a two-port with a feed-back-factor equal to the
ratio between the port signals. It is obvious that the
product of the two factors becomes equal to one. The product
is called the Barkhausen Criterion or the "Allgemeine
Selbsterregungsformel" in German language.