Barkhausenszabály

Barkhausenszabály, or Barkhausen's criterion, is a fundamental principle in electronics that describes the conditions required for a circuit to oscillate. Developed by the German physicist Heinrich Barkhausen, it states that for sustained oscillations to occur in a feedback amplifier, two conditions must be met. First, the total phase shift around the feedback loop must be an integer multiple of 360 degrees, meaning the signal returns to its original phase. Second, the magnitude of the open-loop gain of the amplifier must be equal to or greater than unity, or 1. This ensures that the amplified signal fed back is strong enough to overcome any losses in the circuit and sustain the oscillation.

If the gain is less than unity, the oscillations will eventually die out. If the gain is significantly greater than unity, the oscillations can become unstable and lead to distortion. Therefore, Barkhausenszabály is crucial for designing stable and predictable oscillators used in various applications, from radio transmitters to signal generators. The criterion highlights the delicate balance between amplification and phase shift necessary for self-sustaining oscillations.