[Coco] Project Sneak Peek

[Richard E. Crislip]

On Thu, 21 Jul 2016 14:31:50 +0000 (UTC)
Salvador Garcia via Coco <coco at maltedmedia.com> wrote:

> Although Mathieu sent you the link of links, I'll answer your
> question here. PWM is YAA* for Pulse Width Modulation and is a way to
> modulate using the duty cycle. The modulation can be used to encode
> data or to control power transferred.
> 
> For example, suppose we have  a wave that looks something like
> 000000111111000000111111000000111111 where 0 is the low level (off)
> and 1 is the high level (on). Here the duty cycle is 50/50 because
> the wave is on half of the time and off the other half, as
> represented by the 6 zeros off and the 6 ones on. If I change the
> duty cycle to say 80/20, now the level is on 80% of the time and off
> the remaining 20%.
> 
> Using the duty cycle I can now, for example, dim an LED. A straight
> forward way of dimming an LED is to decrease the voltage; however,
> what if the voltage is not variable? In this case, I can use a
> programmable device to establish a duty cycle for the voltage going
> to the LED. Using the example above, if the duty cycle is 50/50 then
> that means that the voltage going to the LED will be Vcc half the
> time and 0v the other half. This will cause the LED to glow at half
> the brightness of Vcc, not because its voltage varied (which it did
> not), but because of the time that it is ON and OFF. If I change the
> duty cycle to 80/20 then Vcc will be Vcc 80% of the time and off the
> remaining 20%. This will cause the LED to glow brighter than the
> previous 50/50. What if I invert the duty cycle and now have 20/80?
> In this case the LED will only have a slight glow because it will be
> off 80% of the time and on the remaining 20%.
> 
> Since sound is a frequency, PWM can be used to encode the audio
> signal by varying the duty cycle. Voltage regulation is the
> adaptation of an input voltage to a desired output voltage. If I have
> 9v, but require 6v, I can use PWM with the correct duty cycle to
> limit the output and thus generate the desired 6v. I hope this
> helps :-) Salvador
> 
> *Yet Another Acrionym
> 
>       From: Richard E. Crislip <rcrislip at neo.rr.com>
>  To: coco at maltedmedia.com 
>  Sent: Thursday, July 21, 2016 8:35 AM
>  Subject: Re: [Coco] Project Sneak Peek
>    
> 
> 
> OK <Ignorance on> what is PWM? TIA <Ignorance off>
> 
>   
> 

Thanks to both of you for educating me. I learned something, the day
wasn't wasted 8-).