CD4093 oscillator frequency

On 12/21/2015 9:33 PM, Ecnerwal wrote:
> In article <n5a3t6$hgs$1@dont-email.me>,
>   "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> wrote:
>> M Philbrook wrote:
>>>
>>> Sounds to me the coconut business is slowing.
>>
>> Maybe the migrating swallows will bring more.
>
> African or European swallows?
>

Barn.

-- 
Grizzly H.

Phil Hobbs wrote:
> On 12/19/2015 04:17 PM, Robert Baer wrote:
>> bitrex wrote:
>>>
>>> I'm buidling a little relaxaton oscillator for a project using a
>>> cd4093 quad nand gate with schmitt trigger inputs. I'm using a
>>> 200 ohm resistor and a 100n cap in the RC network.
>>>
>>> If I've done my calculations correctly, I was hoping to have an
>>> oscillator at around 30kHz. But my frequency counter is only
>>> showing around 8. Supply voltage is 5V.
>>>
>>> I understand that the frequency is dependent on the hysteresis
>>> thresholds, which are device dependent, but I didn't expect it to
>>> be that far off. Anything to check?
>>>
>>> Can I drop a crystal or ceramic resonator across the resistor to
>>> "lock" the frequency?
>>>
>> For practical purposes, the threshold(s) are one-half of the CMOS
>> supply voltage (at room temp).
>> Reasonably dependable.
>>
>
> "half" in the sense of "anywhere between one third and two thirds."
>
> Cheers
>
> Phil Hobbs
>
   Hmmm..data sheet curves indicate what you said, but those i worked 
with were all rather close to one half CMOS supply. Maybe because they 
all were RCA and "wanted" to be contrary to those data curves?

On Mon, 21 Dec 2015 18:26:56 -0500
M Philbrook <jamie_ka1lpa@charter.net> wrote:

> In article <20151221184958.21849587.joehey@mailinator.com>, 
> joehey@mailinator.com says...
> > 
> > On Sun, 20 Dec 2015 22:16:53 -0500
> > "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> wrote:
> > 
> > > Joe Hey wrote:
> > > > On Sun, 20 Dec 2015 16:34:36 -0500
> > > > "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com>
> > > > wrote:
> > > >
> > > >> Tom Del Rosso wrote:
> > > >>> John Larkin wrote:
> > > >>>> On Sat, 19 Dec 2015 10:52:07 -0500 (EST), bitrex
> > > >>>> <bitrex@de.lete.earthlink.net> wrote:
> > > >>>>
> > > >>>>>
> > > >>>>> I'm buidling a little relaxaton oscillator for a project
> > > >>>>> using a cd4093 quad nand gate with schmitt trigger inputs.
> > > >>>>> I'm using a 200 ohm resistor and a 100n cap in the RC
> > > >>>>> network.
> > > >>>>
> > > >>>> 200 ohms is way too low. Scale up R and scale down C, by
> > > >>>> 20:1 at least.
> > > >>>
> > > >>> Here's another stupid question from me.  If the output
> > > >>> impedance inflates the value of his R then why is his
> > > >>> frequency lower than he calculated?
> > > >>
> > > >> Nevermind.  I wrote that a few seconds ago standing on my head.
> > > >>
> > > >
> > > > Thot so. I couldn't believe what I was reading. :)
> > > 
> > > I'm having a lot of senior moments lately.  It's got me a little
> > > worried frankly, but worrying about things might be the reason.
> > > 
> > 
> > A tablespoon of coconut oil a day keeps Alzheimer away[1][2][3].
> > 
> > joe
> > 
> > 
> > [1] http://www.alzheimers.net/2013-05-29/coconut-oil-for-alzheimers/
> > [2] http://www.ncbi.nlm.nih.gov/pubmed/26667739
> > [3] http://www.ncbi.nlm.nih.gov/pubmed/25997382
> 
>  If only you can remember to take it!
>  
>  Now what was it we were talking about?
> 
>  Sounds to me the coconut business is slowing.

Nah, that's all conspiracy. :)

joe

> Jamie
> 

Ecnerwal wrote:
> In article <n5a3t6$hgs$1@dont-email.me>,
> "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> wrote:
>
>> M Philbrook wrote:
>>>
>>> Sounds to me the coconut business is slowing.
>>
>> Maybe the migrating swallows will bring more.
>
> African or European swallows?

Only an African swallow could possibly carry the weight.

If anybody ever asks you for the capital of Abyssinia, don't sweat. 
Just say, "What do you mean?  The modern capital or one of the many 
ancient capitals."

It's a shame that guy didn't think of this.

--