Sa slike se da viceti da možete da upotrebite, :-), fazni regulator, triac. Piše lepo "Dimmable ..." .
Ali, evo ti nešto zanimljivije, nešto iz Elektora iz februara 2009-e.
"Electronic Transformers
Dear Elektor — as a staunch
reader since issue # 1 I’d like
to provide some information
that’s supplemental to your
article ‘Electronic Transformers
Revealed and Explained’ in
the December 2008 issue.
These ‘transformers’ are
actually switch-mode power
supplies or, more accurately,
‘power auto oscillators’ and
most of them are based on
application note AN528 from
STmicroelectronics. Even if
bipolar transistors have been
replaced by MOSFETs in
recent models, the principle
remains the same. The application
note provides a detailed
operation of these supplies,
and has good educational
value.
Interesting as that may be, if
we look at the schematics in
detail, it’s apparent that these
supplies may be modifi ed to
act as dimmers. The oscillator
is triggered by a diac using
an RC network. If a potentiometer
with value 10 R is inserted
in series with R, a dimmer is
created with a range close to
0-100%.
Sure, you have to know a bit
about electronics but I would
expect Elektor readers to be
able to locate the resistor (if
necessary, consult the application
note), and lift up one
of its legs. The resistor value
is usually between 100 kΩ
and 220 kΩ, depending on
the model and the associated
capacitor. Do not remove the
resistor completely, as it will
act as a protection if the pot is
set to zero. In the absence of
the fi xed resistor, a resistance
below the original value could
well cause the supply to go up
in smoke.
An even more exciting modifi
cation is to link the potentiometer
to a switch. This setup
allows a smooth switch-on of
the load, which will benefi t the
life expectancy of the bulbs
(effectively preventing the
high inrush current when the
fi lament is cold). It is also
much more agreeable in the
bathroom, particularly in the
morning when harsh lights
normally greet you there.
Electronics enthusiasts may
reap another benefi t from
these cheap supplies by simply
rectifying and smoothing the
output voltage, and so make a
cheap, powerful, 0 to 15 volts
adjustable supply.
Be sure to observe electrical
safety, as the potentiometer
terminals are connected to the
rectifi ed AC mains voltage. A
potentiometer with a plastic
spindle must be used, preferably
in combination with an
ABS enclosure.
Alain Caillard (France)
Electronic Transformer for
a 12V Halogen Lamp,
Fichera, P. and Scollo, R.,
AN528/0999, STMicroelectronics,
1999.
www.st.com/stonline/products/
literature/an/3707.pdf"
Link sa kraja teksta, ST AP
A primetio sam da ovaj trafo poseduje još jedan SMD tranzistor, pa verovatno poseduje i zaštitu od kratkog spoja. Proverite u odnosu na šemu datu u AP.
Diode mogu iz PC napajanja, a kondenzator je mislim nepotreban.