> =

> > that has internal clock good to 5% , input
> > from switch, output to triac and output to 20 ma bi-color LED.
> > Should the LED be buffered ?
> > I want to run this off 220VAC / 110VAC as cheeeeeply as possible.
> > Should I use a resistor and zener ?
> >
> > Unit will have PIC, one pushbutton, one triac, one bi-color LED, AC
> > plug and socket.  It will be an inline power switch ( on/off only )
> >
> > Best
> > Gus

Since you are making this transformerless you need to make sure that the =

insulation requirements regarding accessible parts, especially for the swit=
ch =

and the LED are satisified for a working voltage of 230VAC.

For the currents you are going to use (20mA LED) you might want to use a =

capacitor instead of a resistor. Note that the capacitor should be of a typ=
e =

X2. Even so, 20 mA plus the current for the rest of the circuit might be to=
o =

much.

If you have not done so already, take a look at Microchip's application not=
e =

AN954 about transformerless powersupplies.

<http://ww1.microchip.com/downloads/en/AppNotes/00954A.pdf>

/Ruben

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

-- =

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