At 06:43 PM 7/28/2009, you wrote:
>Sorry for the possibly repeated question.....
>I want the cheapest PIC 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

Not SOIC-8, but maybe you could use the PIC10F200- SOT-23-6 and around 30
cents (USD) in volume ... unless there is another I/O requirement you
have not mentioned.

Suggest you not run the LED at anywhere near 20mA- get a decent LED and
drive it directly at 5mA or so. In volume you can get whatever LED chips
you like in a dual LED.

A capacitor/zener power supply is more practical than a dropping resistor..
the circuit will run much cooler, and you already have a triac to deal with.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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