[sdiy] Simple "theremin" schematic question

[harrybissell]

Hi Pat

Pat Kammerer wrote:

> Hello all,
>
> I finally got a part I needed to throw this together, and then realized I
> was one step short of understanding the schemtaic.
> http://www.maxiespages.com/images/Theremin/simple.jpg
>
> What I need to know is what the plus in a circle is at pin one of both 4093
> chips.  Is this supply voltage, and used for a reference?  Or is this
> something else?

Supply voltage

>
>
> Also I noticed that there is not mention of pins 4,10, and 11... anyone know
> if I should do anything with those?

4, 10 and 11 must not be connected

>
>
> Hypothetically, If I were to make this from HCT or LS TTL chips instead,
> would I run all of the unused inputs to the supply voltage instead of
> ground?  Would I need a resistor?

you would NOT use LS TTL ~or~ HCT to build this. It is quite specific to 4000
series
CMOS.  It uses the unique properties of the 4093 !

H^) harry

>
>
> Thanks in advance!
> Pat