>
> Can anyone help me with a vaguely PIC related problem...?
>
> I have a project in which I need to control the brightness of a 12V lamp
> from a PIC.  The lamp has to go from maximum brightness to the off state.  I
> am planning on implementing this using varying mark-space ratios so to
> minimise power loss.
>


I once made a similar system with a free running 8 bit (ab 100kHz)
binary counter, a binary magnitude comparator and a power
transistor. When the value that was set on a PC's parallel
port was exceeded, the transistor turned off.

I used a 24V halogen lamp, which needed about 128/255 (1/2 duty
cycle) to light - so the adjustment was made about 128-255
and 0 to turn it completely off.

This PWM solution can easily be implemented
on a pic - if you just know how...

Best regards, Vesa


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