Zobel Netværk

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Hej

Nogle der ved hvordan et Zobel Netværk udregnes??
Mit udgangssignal er altid 10KHz og min "last" spole er 75uH 4.71Ohm

Hvordan bestemmes R og C?

på forhånd tak


Re: Zobel Netværk [ Boucherot cell ]
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Hej Søren

Her er noget fra et af mine tidligere indlæg:


Udgangen bør belaste af et zobel-netværk:
http://www.trueaudio.com/st_zobel.htm
Zobel Or No Zobel ?:
http://www.diyaudio.com/forums/showthread/t-120748.html
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:
http://www.diyaudio.com/forums/showthread.php?threadid12%5679

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


-


http://en.wikipedia.org/wiki/Boucherot_cell
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.
..."


( http://en.wikipedia.org/wiki/Zobel_network )

/Glenn

Re: Zobel Netværk [ Boucherot cell ]
Super sider

1000tak

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