[sdiy] Unused opamps in multi-opamp ic / Re: triangle core VCOcomparators

[David G Dixon]

When I have an unused opamp in a circuit, I always ground the + and connect
the - and out to make it a ground follower.  I don't connect the output to
anything else except -. 

> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at dropmix.xs4all.nl] 
> On Behalf Of Rick Jansen
> Sent: Thursday, February 25, 2016 12:28 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Unused opamps in multi-opamp ic / Re: 
> triangle core VCOcomparators
> 
> 4.2.1 in that article has an interesting section on what to 
> do with unused opamps in a multi-opamp ic...  Comments? 
> (Apparently I did it wrong, a few times..)
> 
> rick
> 
> > On 25 Feb 2016, at 21:15, Rick Jansen <rick.jansen at xs4all.nl> wrote:
> > 
> > This month's (March/April) NL Elektor has an article on the 
> difference between actual comparators and opamps. True 
> comparators are (much) faster, and can reach rail voltages, 
> and so not rely on the amplification factor of the opamp. 
> Also, the output stage of many opamps is not suited for 
> comparator functions, and can even damage them.
> > 
> > The end of the article refers this document: 
> > http://encon.fke.utm.my/nikd/latest/sloa067.pdf
> > 
> > Bruce Carter : opamps and comparators , don't confuse them.
> > 
> > R.
> > 
> >> On 18 Feb 2016, at 01:48, Chris McDowell 
> <declareupdate at gmail.com> wrote:
> >> 
> >> howdy,
> >> 
> >> I'm wondering about the choice of comparator for triangle 
> core VCOs. I've seen it done a few ways, like Thomas Henry's 
> discrete comparator, or the LM311 in J3RK's (STROH Modular) 
> VCOs on Muffs, and my own builds just use TL07x and work 
> -pretty much- great. But I'm wondering what the experiences 
> and preferences are of you here on the list. Fast op amp? 
> Real comparator? Doesn't matter? I'm aware that it only 
> matters as much as HF-Tracking matters, but I'm interested in 
> opinions anyway. 
> >> 
> >> Cheers!
> >> Chris
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