[sdiy] VC Switch schematic?

[Scott Bernardi]

Probably the easiest way to implement voltage controlled switches is with
analog switches like the DG201 series. These have 4 SPST switches per
package that can be controlled by a logic signal for on/off.  They can
handle full range analog signals (i.e., +/-15v).  They are a bit pricey,
though.
They next alternative would be to use the cheap 4066 CMOS switches.  These
can take a maximum of 16v across the chip, though, so you would have to
make some +/-7.5v supplies to power them, and then the logic levels are
-7.5v (off) and +7.5v (on).  They can handle analog signals up the the
supply values (+/- 7.5v), which is a problem if you need to handle 10v
peak signals.

If you want to implement a "select one of many" function you can use a
demultiplexor.  There are analog ones and CMOS ones available with the
same restrictions as above. Juergen Haible has an interesting circuit, the
"Interpolating Scanner" which does a demultiplex function with a smooth
transition from one input to the next (crossfade) under voltage control.
http://home.t-online.de/home/jhaible/jh_ipscan.html

ElmacacoX at aol.com wrote:

> Hey everybody,
>
> Does anybody have a VC switch schematic on their website or something?
> I'm looking to add one or two to my SBM.
>
> thanks,
>
> Ed

--
Scott Bernardi
sbernardi at home.net