On Fri, 23 Mar 2007 13:55:19 -0500, John Fields wrote:
On Fri, 23 Mar 2007 16:37:48 +0000, Eeyore
John Fields wrote:
Eeyore wrote:
John Fields wrote:
Eeyore wrote:
Trevor Morton wrote:

I am still developing my abilities and find myself all too often
struggling with op amp design.

Can anyone here suggest an "all purpose" amplifier built around a
readily available op amp and transistor follower that will operate
within the specifications below? Preferably without changes in
componentry except to upgrade the power transistor depending upon load
requirements.

DC coupled with frequency response DC to 20KHz
Input signal level 1-2V
4 to 12 volts single supply
Low power DIP op amp, suited to battery operation if required
Variable gain, unity to 10 via trimpot (dependent on rail V)
Swing as close to rail as practical without using a rail-to-rail amp
Drive resistive load 20 to 200 ohms (dependent on power transistor
used.)

What you're desribing is an amplifier. NOT an op-amp.

Funny, it seems that's what he was asking for in his second
sentence.

So why "op amp" in the thread title and above "Low power DIP op amp....." ? I
suspect here may be some confusion in the OP's mind.

I see no confusion; he seems to know exactly what he wants.

The "Low power DIP op amp" is what he'll use to drive the output
transistor, the combination being the "all purpose" amplifier he
wants, while "All purpose SS op amp" is less clumsy than "All
purpose SS op amp amp."

You reckon he only needs *one* output transistor ?

That's what he wants. Can't you do it?

Nat Semi has a pretty cool app note:
http://www.eetkorea.com/ARTICLES/200...6_AMD_AN03.PDF

Cheers!
Rich