cupoftea
Advanced Member level 5
Hi,
Imagine You have a variable gain NPN in the Flyback feedback loop...like as in page 7 of this...
DER-243
...You obviously dont want it there...but must have it, to keep opto current down.
So which NPN has the least variation in gain?
The Flyback has VAC in = 90-125VAC, and will be in continuous mode for most of that, though not very deeply so.
Also, its a TOPswitch-HX, so its voltage mode.
Fsw = 65kHz, Lp=1.07mH Np/Ns = 84/19
There is no fan in the unit...its just convection cooling as best as poss in the enclosure.
MMBT3904
Imagine You have a variable gain NPN in the Flyback feedback loop...like as in page 7 of this...
DER-243
...You obviously dont want it there...but must have it, to keep opto current down.
So which NPN has the least variation in gain?
The Flyback has VAC in = 90-125VAC, and will be in continuous mode for most of that, though not very deeply so.
Also, its a TOPswitch-HX, so its voltage mode.
Fsw = 65kHz, Lp=1.07mH Np/Ns = 84/19
There is no fan in the unit...its just convection cooling as best as poss in the enclosure.
MMBT3904