[sdiy] SEM LFO square wave mod...

[ChristianH]

On Sat, 28 May 2011 11:57:11 +1000 "Paul Perry" <pfperry at melbpc.org.au> wrote:

> Anyone playing around with a CA3080 - or any similar OTA like the LM13600 - 
> needs to know that the maximum curren tthat can go into pin 5 is 2mA.
> DO NOT connect it directly to a voltage, that will kill it stone dead in a 
> microsecond.
> I always connect a 10K resistor to pin 5 (or the equivalent pin) because 
> that prevents current overload, no matter what you connect it to. It isn't a 
> control voltage input, it is a CURRENT control input.
> By running voltage through the resistor, you make it look roughly like a 
> voltage control.

And another thing is important too - with this poor man's V to I
conversion using just a resistor, the input voltage is not referenced to
GND level, as might be expected. To completely close the OTA, the
voltage applied has to go down to -15V.

Christian