dumbass semiconductor question

[media at mail1.nai.net]

At 6:44 PM -0500 06/11/98, tomg wrote:
>>Thank you for taking the time to draw the diagram.  What's a 4066??
>
>A CD4066 is a CMOS quad bilateral switch. The 4066 is a better choice because
>you can switch anything just as if you had a SPST connected instead of an ic.
>Switching voltage is fine as long as the voltage does not go above +V or below
>gnd. If you need to switch a negative voltage it can be run on a +- 7.5V split
>supply but no more. You can even connect the control pin to inverters or
>buffers for logic/CV switching.
>
>>What I am looking for is a simple three-legged animal that is a normally
>>closed switch, that opens when it receives a voltage.  I guess I'm just
>>surprised that they don't make such a thing.
>
>They did...they just put 4 of them in one package it's called a CD4066.

No, according to your diagram the CD4066 is normally open, not normally closed.

>I guess you want to use a transistor.
>
>                 +V
>                 ^
>                 |
>                 /
>                 \ 10K
>                 /
>                 \
>     100K        |----o
>               |/
> i__/\/\/\-----+
>               |\  2N3904
>                 V
>                 |
>                -+-
>                 -
>
>The output is normally high if the input is low. If the input is high the
>transistor turns on and the output goes low.

Right, that is what I could put in front of a 1/4 4066 to get what I want
(imagine I could also use another 1/4 4066 or a logic inverter in place of
the NPN).

How much are a CD4066's??  I'm presuming they need their own power supply
and come on a dip chip.  I was trying to avoid adding in another PCB.

Someone else sent me this:

>
>                       +Vcc
>                         |
>                         |
>                        10K
>                         |    +------>
>                 +---R2--+    |
>                 |       |    |
>                 |       |    |
>               |/        |  |/
>  Vinput --R1--|  Q1     +--|  Q2
>               |\           |\
>                 |            |
>                 |            |
>                 |            |
>                 |            |
>                gnd          gnd
>
>
>  So:
>    Input = OFF,  Q2 ON
>    Input = ON,   Q2 OFF

I'm thinking maybe R2 isn't necessary.  Anyway, I was looking for a single
part I could just fly on, but at this point, using two common NPN's seems
the least expensive way to go if I have to build a little perfboard.

THANX!!

PEACE OUT :)



P.S.  So they put the catalog in an envelope, drop it in the mail and then
      what??   It get's eaten by termites??  Intercepted by the CIA??  What??