sp300b

Bolje ti je da zavrsavas skolu (i babela i LDR)...

I'll take it...samo gledam Passove hladnjake na XA30.5 i cudim se kako mu izdrzavaju...Mora da se greju na nekih 75 stepeni, a on tvrdi da je 53 p.s. edit: citat iz passovog clanka "Leaving..." As a practical matter, this means that our X (Class AB) amplifi ers are biased to dissipate roughly half of their rated output power. The XA (Class A) amplifiers are biased to dissipate roughly three times their rated output power. Da li ovo znaci 3 x 30 = 90 W?, a ja se "patim" i pokusavam da se uglavim na 100 W.... ili da ja malo odmorim mozak kojih dan-dva (ili nedelju/dve)

Sve se slazem. P = R * I^2. Sto se Disipacije tice, ona je jednaka naponu napajanja (u odnosu na gnd x 2) i jos puta 2 struje (levo i desno). Ako pricamo o napajanju od +/-20V onda imamo zahtevanu struju od 1.25A po "grani" bridge pojacavaca za 100W disipacije Korisna snaga u tom slucaju iznosi R* I^2 = 12,5 W...a ja razmisljam o 25W ... U svakom slucaju, hvala VAM kolega Impulse na zelji da pomognete.

I NP i ja pricamo o push-pull u A klasi, samo on spominje 30W, a ja 25 W...uz max dispaciju u mom slucaju od 100 W na hladnjaku...

Ok - kontam, ali kako onda Pass deklarise XA30.5 kao 30 W?

Potrebna mi je konsultacija. Naime, razmisljajuci o disipaciji za XA.5 Concept, a uvazavajuci NP objasnjenje, te obzirom na tabelu datu u dokumentu Leaving class A, pokusavam da shvatim da li mogu na racun manje korisne snage (nesto tipa 25 W) da idem sa disipacijom od 100W (pricamo za jedan Mono kanal)? Naime u svom Babelu imam hladnjake koji se regularno temperaturno ponasaju pri cemu trose 100W disipacije. - Racunajuci na identicne hladnjake, koji bi to trebalo da budu moguci Naponi i biasi ? Na kraju krajeva, ja sam nesto skontao da Pass u XA30.5 koristi plus minus 23 V, ali ne razumem bas sa kojim biasom?

Details

Cascode The cascode therefore, are BJT transistors inserted in series in the drains of the JFET. Their bases are maintained at a constant Voltage potential. As the potential of the base is constant (in the order of 10V for UGS), potential of the Drains will also be fixed, and 0,7V will be less than the potential of the bases. What makes that is ultimately drains the JFET will be at a constant potential. The VGS of JFET in normal operation is relatively low, we will quickly say that the VDS voltage at the terminals of JFET remained stable, or at least varies very little. With this little trick we have three very interesting conclusions: First, that the voltage of the JFET is within the 10V, that means we have reduced the power dissipated in the JFET: for example, for a current of 3.5mA, a JFET will dissipate 35mW, while without cascode, it should remove more than 65mW. It has therefore gained in overall thermal stability. Second, as VDS is roughly constant, it will have the effect of linearization of the behavior of the JFET. For an ideal transistor, the various "rights" to VGS = CSTE are parallel and slope zero. In reality, they are not, and the slope is not zero. So if the voltage of the drain JFET varies, the current drain of the JFET will also vary ... And where is the problem, you say? Well, is that we would like the current drain of JFET depends only on the input voltage, and not something else. (I remind you that had asked id = gm*vgs) The cascode, setting the potential drain, thus to minimize this non-linearity, and working on a much closer these curves (in red zone ☺), where you can take that will variation of drain current negligible according to VDS. Okay. Purists will tell me that VDS is to be maintained constant, and not only the drain voltage, as is done in the hope that the voltage source does not move too much. That's true. But I have not wanted to break the head, and you are free to try both versions, after all. With all that, I forget to mention the last effect of the cascode, the extension of the bandwidth. B

itd...

Da se ne zaboravi ... Btw - odlicno objasnjenje za siroke narodne mase koje je sheff uradio. nazalost na francuskom samo...za svoju dusu sam pokupio i google prevod na engleski, pa pokusavam da uklopim celu pricu...

Topla preporuka za sve moguce marufetluke sa slikama - FSViewer i ne boli glava

Nedostaje sta ?!

Dobrodosao u klub Babelovaca

Nameracio sam se da izmerim Vbe za potrebe uparivanja tranzistora, trazio informaciju na Internetu, a posto nesto bas i nisam naleteo na istu, seo i nacrtao slicice koje objasnjavaju.Stoga, evo neka ostane ovde zapisano.(U mom slucaju, hteo sam da umerim na Ic = 5mA).

Najgore kad Admini prave OffTopic..c,c,cKoliku mirnu struju ste postavili na kraju - 2A ?

Za zvucnicki kabl - obratiti se Zenu za savet. On ima najbolji kabl na svetu - belo-plavi ili ti plavo-beli p.s. Ne izdrzah a da ne uputim na moj zakljucak na fifi - doduse za balansiran sistem ;-)

Mali, ali tehnicar

rev B...UGS_rev_A_schematic_04_06_2009_rev_B.pdf

Hi Manu. Btw - something like this...Changes of the element's value are highly possible.So far, no big thinking done around thisUGS_rev_A_schematic_04_06_2009.pdf

Jes' pa da onda rastrubis svima

U pravu si - korigovacu