"Phil Allison" wrote in message
...

"Arfa Daily"
No, it's regulated DC.


** With just two transistors and one mosfet ?

That is what you have told us.

And SFA else.


You shouldn't take things quite so literally, Phil. I was talking about
the primary side only when I said that, but yes, it pretty much has a
pair of small TO92 transistors, and a TO220 mosfet. Obviously, it also
has input filtering, a bridge, made of 4 discrete diodes, a main filter
cap, and assorted R and C to make those two little transistors into an
oscillator. About 20 components altogether. The secondary side is exactly
like any other fixed voltage typical design, and there is, of course, a
perfectly normal 6 pin opto for regulation feedback. Better ?


** All that needed to be in the first post, plus the operating frequency.

No it seems the whole story was BS anyhow.



.... Phil




Well, actually, it didn't, as it was irrelevant to the situation. How the
mosfet receives its drive is neither here nor there in regards to what's
going on at its drain. As long as it has a pulse width modulated 'square'
wave of sufficient amplitude to fully drive the gate, how that waveform is
produced is of no consequence. It actually looks, on this supply, pretty
much exactly the same as the drive waveform on some of the others that the
company have sent, and which use a dedicated PWM chip to produce the drive.
As to the operating frequency, yes, I probably should have stated this, but
most supplies of this sort of size, operate between 40 kHz and 80 KHz, as
would be understood by anyone who works with them regularly.

And why do you think it's all bull**** ? Do you think that I just sit here,
and think to myself "Hmmm. I wonder what dumb-arsed story I can come up with
to start a thread with ?" No, of course not. It's just you, as ever,
spoiling for a fight. Well listen up pal. If you've got anything interesting
to add, as you sometimes actually do, then go ahead and say it. Otherwise,
no one is interested in *your* bull****. Ok ?

Arfa