[sdiy] PWM, Vactrols & Opto-Isolators

[Dustin Withers]

The application is a mix of my own interest and that I've noticed many
of these inexpensive micro controller boards have many PWM outs. I'd
like to be able to do digital control of analog circuits. It seems my
best bet maybe some kind of DAC though, right?

dustin

On Wed, Jan 13, 2010 at 5:37 PM, Tom Wiltshire <tom at electricdruid.net> wrote:
> Dustin,
>
> If you're looking to get a DC level out, then I'd say, yes, 30KHz is high.
> You could set the RC filter frequency for 10Hz and the pulses would be more
> than 3 decades above the cutoff, which ought to give a decent filtering
> action even with such a simple layout.
>
> Jay's comment's about linearity are very pertinent though. PWM->LED
> linearity isn't going to be perfect, and LED->LDR linearity will add it's
> own twist too. How accurate do you need it? What's the application?
>
> Regards,
> Tom
>
>
> On 13 Jan 2010, at 19:03, Dustin Withers wrote:
>
>> Tom,
>>
>> Is a pulse frequency of 30Khz considered high?
>>
>> Thanks for the help,
>> -dustin
>
>