[sdiy] More about the Aries VCO

[Peter Grenader]

My little triangle core VCO uses a 311 also.  Runs like a top.

...and i've wired just about everything imaginable up wrong -- including my
shoes, on a few occasions.

- P 


James Patchell wrote:

> I myself have also used the LM311 as a comparator in both saw (ASM-1 type)
> and triangle VCO's with excellent results.  Don't know why, but in
> breadboards, I always manage to wire the power supply pins up
> wrong....(somehow, I always got them correct on PC boards....)....
> 
> At 11:56 PM 6/14/2004 +0000, harrybissell wrote:
>> The 3080 has a slew of like 80V/us which puts it above opamp class (as
>> comparator)
>> but below the std LM311 etc. It is a very well behaved comparator and i
>> have used
>> it
>> often as such...
>> 
>> H^) harry
>> 
>> Ian Fritz wrote:
>> 
>>> At 04:04 PM 6/14/2004, JH. wrote:
>>>> Now that I know the internals of the expo onverter, I've taken a
>> closer look
>>>> at
>>>> the whole thing.
>>>> 
>>>> This CA3080 based schmitt trigger is very clever! Must be pretty fast
>> *and*
>>>> precisely bouding at fixed level without saturating.
>>>> (Does anybody know at what current it is working, i.e. the value of the
>>>> resistor at pin 5 of U4 ?)
>>>> 
>>>> I still wonder if it is *that* fast (and if the transitors have such low
>>>> rbb) such that
>>>> it doesn't need any HF tracking compensation ?!
>>> 
>>> I haven't looked at the Aries, but the 3080 as Schmitt trigger was used by
>>> Bernie in the ENS-76 series.  See EN#75, p. 10, or the builder's
>>> guide.  The integrator is a 3080 driving a 1 nF cap buffered by a 3140. The
>>> Schmitt trigger output is diode clamped.   There is no hf
>>> compensation.  The tuning wasn't measured to high precision, but it looks
>>> like it goes sharp (!) by 0.5% at the high end (24 kHz).
>>> 
>>> Ian
> 
> -Jim
> ***************************************************************
> http://www.oldcrows.net/~patchell
> 
> ***************************************************************
> 
>