[sdiy] Inverters as opamp subsitutes

[Scott Gravenhorst]

Tim,

You may already be aware of this, but the difference between a 4049UB and a
4069UB is in the symmetry of the complementary pairs.  In the 4069UB, they are
symmetrical (current drive capacity for high and low output levels are equal),
whereas the 4049UB offers

"TIm Daugard" <daugard at sprintmail.com> wrote:
>
>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.
>
>

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