[sdiy] Inverters as opamp subsitutes

[TIm Daugard]

From: "René Schmitz" <uzs159 at uni-bonn.de>

> components. Just like with OPs. Infact you can think of the gate symbol
> as a poor mans opamp, which has its + input tied to Vcc/2 internally and
> the only the - input brought out.

I have actually relooked at this very fact. In some circuits - distortion boxes
and others - there are opamps being used as high gain inverters or comparators.
As high gain inverters the 4049 works well.

The circuit I was looking at was going to require 6 opamps configured as
integrators. I breadboarded the circuit with a 4049 and it worked well. The 4049
might be useable anywhere there is multiple opamps set up as inverters with the
+ input tied to a 1/2 supply reference. The circuit reduces down to a 4049 and
two quad opamps - down from five quad opamps. This saves board space, wiring,
and is about even in cost. Now I only have to make the front panel.

Tim Daugard
30.4078N 86.6227W
With - thanks to Ivan the terrible - a huge pile of fire wood in the front yard
and 150 Sq Ft of front panel material in the side yard.