Analog Computer

[Bill Layer]

Hi Scott, 
>
>I believe that the term op-amp or operational amplifier was coined by
>the analog computer field.  "Operational" as in arithmetic operations, the
>most common being the 'sum'.  Is there much different about our modern op-amp
>integrated circuits from the orginal op-amps used in analog computers? 

I'm not so sure about this. AFAIK, the op-amp was designed in 1947 by Mr.
Filbrecht (did I get the spelling right?) for use in his tube regualted
power supply. Two vacuum tube op-amps (5 tubes apiece) were employed to
control the two grids of a 6080 (a 6AS7 type) in his bipolar supply.

The Atma-Sphere MP-1 power supply (+/-225VDC) employs the exact same
scheme, but uses two TLO-82 op-amps for pratical reasons. 

If you've never heard of Atma-Sphere, it is worth your time to visit the
sites. 

Start at <http://www.atma-sphere.com> and then go to the ASOG site. You'll
probably encounter a link to my (new) pages on that server as well... The
Atma-Sphere mailing list is also a great source of DIY tube info.

Check it out!



 
Bill Layer
"Quantity has a Quality all of it's own." -JL