[sdiy] 3080/13700 OTA question

[Ian Fritz]

At 03:50 PM 1/2/2009, Tim Ressel wrote:
>Ah. I tried reversing the 10K and 2.2M with no luck. The OTA just loads 
>down the 1uF cap preventing it from developing significant voltage. From 
>your results I suspect the circuit will work if I juggle some values, but 
>if the performance was that poor then why bother?

Yes, I see that now.  The rates decrease with lower duty cycle, so the 10 k 
defines the fastest time not the slowest.  Maybe it's the 2.2M and 680k 
that are swapped.  It sure seems like the pulldown resistor needs to be 
larger than the supply resistor.

Ian