[sdiy] Re: Doing it all in 4069s

[Magnus Danielson]

From: "tomg at efm" <efm3 at mediaone.net>
Subject: Re: Doing it all in 4069s (Was: Re: [sdiy] New Vco (new images))
Date: Sat, 29 Sep 2001 14:06:50 -0400

Tom,

> What Magnus wants to do is use inverters to build opamps 
> and replace the 072 still using  the dual npn.

Indeed.

> Both of the opamps used are inverters. You might have to run a separate 
> 4069 on a split supply of some sort or maybe use a split 
> supply for the whole thing....but maybe......It should be 
> possible... 

Well, maybe a second 4069 would not have to be used. It would actually
be quite neat to get a full oscillator core out of a 4069 a transistor
pair and a handfull of passives.

> Of course it's not really necessary...Rene did it without any 
> opamps at all...Using something like that Tau vco Jim posted
> as an example you can build a discreet current sink. Then
> all you need is a discreet mixer......you can eliminate opamps
> and inverters.  

Indeed, but there is 3 inverters and they ougth to be used, and
getting buffering isn't a bad thing.

Cheers,
Magnus