[sdiy] VCO waveform logic selection

[Tom Wiltshire]

On 12 Sep 2007, at 12:29, René Schmitz wrote:
>
>> On your webpage you note that the diodes may not be omitted.
>
> Read that as "should".
>
>> Are the protection diodes built into the device inadequate for  
>> this purpose?
>
> Those diodes delimit the amplitude to +-0.6V around GND, while the  
> input protectors do clamp against Vcc and GND. Delimiting the swing  
> at the open switch does reduce the risk of capacitive crosstalk.

I note that on the Prophet 5 schematics, the switches are Quad SPST  
4016's, and are handling control voltages which presumably remain  
positive (0-5V, most likely) since there is only a single diode to  
earth.

Thanks for bringing this up, I hadn't studied this part much before.  
Fascinating!

T.