[sdiy] OpAmp Output Current Question

[Scott Gravenhorst]

Many thanks to Roman, Tim, Harry and Jim,

Here is what I am up to so far:

http://home1.gte.net/res0658s/h11f1_sallen_key.gif

The Rs and Cs of the filter still need to be determined, but
I think the LED
driver is done.  My CV is expected to range from 0 to about
6.5 volts.  LED
current should be 0 to 13 ma with that CV range.  I'll need
to play with the
CV attenuator to optimize it.  Audio input to the filter
will be 8 volts.

I still want to try a Sallen-Key with a 4007/4069UB combo,
but I thought
this H11F1 design would probably have a better chance of
being usable, so
I've decided to start with it.

James Patchell  wrote:
>Generally, at that current level, and depending on the
application, I will 
>use a transistor as an output current booster....NPN if I
need to source 
>current, PNP if I need to sink it....if I need push
pull.....well.....
>
>At 11:02 AM 1/10/2004 -0700, Scott Gravenhorst wrote:
>>I was looking at the spec sheet for a TL072 opamp today
>>wanting to know what the device's maximum usable output
>>current can be.  The only spec given is no-load supply
>>current.  I need to be able to supply up to about 20ma.  Is
>>this reasonable for a TL072 or should I choose a different
part?
>>
>>Thanks.
>>
>>=========================================================
>>- Where merit is not rewarded, excellence fades.
>>- Hydrogen is pointless without solar.
>>- What good are laws that only lawyers understand?
>>- The media's credibility should always be questioned.
>>- Governments do nothing well, save collect taxes.
>>
>>-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>>-- Linux Rex         | RedWebMail by RedStarWare
>>-- FatMan: home1.gte.net/res0658s/FatMan/
>>-- NonFatMan: home1.gte.net/res0658s/electronics/
>>-- Master of Arcane and Hidden Knowledge.
>
>         -Jim
>***************************************************
>I'm a man
>But I can change
>If I have to
>I guess.
>
>Man's Prayer
>Red Green
>
>***************************************************
>http://www.oldcrows.net/~patchell
>
>http://members.cox.net/patchell
>
>***************************************************

=========================================================  
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/FatMan/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Master of Arcane and Hidden Knowledge.