AVR-Chat

At 11:18 PM 1/8/06 +0530, Anurag Chugh wrote:
>why only PWM?.. why not use an R2R ladder instead with precision resistors...
>i know they would hog a whole PORT but arent they easier to implement ??
>and they can do DC output values too... a simple opam in front (voltage 
>follower) will boost current output too...

Not quite in the same line of thought but no one has mentioned the other 
reason to prefer PWM over R2R in some situations and that is power.  Feed 
the PWM into a power device rather than an RC filter and with a slowly 
responding load like a heater tank or a motor the load itself acts as the 
low pass filter and you avoid the losses that a linear solution would 
entail.  At the cost of ending up with high frequency current transients of 
course.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,   be 
they legal, genetic, or physical.  If you don't believe me, try to chew a 
radio signal. "  -- Kelvin Throop, III
http://www.aeolusdevelopment.com/