Zobel Netværk

Hej Søren

Her er noget fra et af mine tidligere indlæg:

Udgangen bør belaste af et zobel-netværk:

Zobel Or No Zobel ?: Citat: "...Zobel (not zombel) is usually always required to load the output stage at HF to damp oscillatiory tendencies. Those that leave it out are either bad designers or lucky. ... The zobel can go before the choke. ... The output inductor is simply there to guarantee your load going inductive at HF. If you drive (long) cables, certain filter topologies, or a piezo tweeter, the load doesn't turn inductive at high frequencies, but capacitive. Here, the zobel scheme falls apart, so you include a series inductor in the amplifier after the zobel, to keep the scheme working properly. ..."

Også vigtigt:

Udgangen bør have et lavpasfilter i form af en luftspole (eng. choke) parallelt med en 2-10 ohms modstand:

Med en operationsforstærker sætter man blot 100 ohm i serie med udgangen, men det er ligesom en dårlig idé med en effektforstærker.

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Citat: "... A boucherot cell (or Zobel network) is an electronic filter, used in audio amplifiers to dampen out high frequency oscillations that might occur in the absence of loads at high frequencies. Named after Paul Boucherot a boucherot cell typically consists of a resistor and capacitor in series, that is usually placed across a load, for stability. ... Zobel networks are used in audio amplifiers to dampen out high frequency oscillations that might occur in the absence of loads at high frequencies. It is the commonly seen series resistor-capacitor combination located directly at the output of the driver stage, just before the output inductor (in analog power amplifiers). Typical values are 5-10 ohms in series with 0.1 microfarads. The network limits the rising impedance of a loudspeaker due to the speaker coil inductance. The output inductor found in most analog power amplifiers used to disconnect the load at high frequencies further aggravates this phenomenon. ..."

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/Glenn

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"Glenn Møller-Holst" skrev i meddelelsen news:gtscbb$1rf$ snipped-for-privacy@news.net.uni-c.dk...