Reply by Anthony William Sloman●July 31, 20222022-07-31
On Friday, July 29, 2022 at 12:43:13 AM UTC+10, Phil Hobbs wrote:
> Paul Badenhorst wrote:
> > On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
> Re: NE566
>
> The 566 is a really crappy oscillator. It's perfectly okay for a
> junkbox project, of course--I've done lots worse things myself--but for
> a real design there are many, much better choices nowadays.
>
> On the simple end, the oscillator of a CD4046 will work as a very
> wide-range VCO with a pretty linear tuning characteristic over about
> 100:1 in frequency, though the center frequency isn't that accurately
> controlled by the RC time constant.
>
> The 4046 has only a square-wave output, so if that's a worry one could
> use one of many dual op amps. One section would be a Howland current
> source driving an integration capacitor with its other end grounded, and
> the other would be a Schmitt trigger controlling the polarity of the
> Howland. That will be better than the 556, but of course needs a lot of
> extra resistors. (On a PC board, one could make both the Howland and
> the Schmitt using one 8x resistor array, so it wouldn't be that many
> parts in real life.)
Another option is to run the 4046 eight or 16 times faster than the sine wave frequency you need, divided it down by eight or sixteen, to get a square wave of the desired frequency, and clock the slower square wave through an eight or sixteen stage shift register at the faster clock rate.
By tacking the right resistor values onto the taps on the shift register , and running all the resistors into a summing junction you can make finite impulse response low pass filter and get a pretty clean sine wave over quite a wide range of frequencies, You use up a lot of E96 value O.1% resistors, and you have to worry about putting a Hamming window on your sinc function resistor vales to suppress Gibbs oscillations, but it can make a nice sine wave over a wide range of frequencies.
--
Bill Sloman, Sydney
Reply by Don Y●July 31, 20222022-07-31
On 7/28/2022 6:27 AM, legg wrote:
> On Wed, 27 Jul 2022 23:27:48 -0700 (PDT), Paul Badenhorst
> <paulbpb@gmail.com> wrote:
>
>> On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
>>> I have benn trying to find a decent alternative to the LM566 VCO. It
>>> does not seem to be sold anymore at reputable sellers and the ones on
>>> EBay (from China) I don't trust to be authentic or unrecycled. Does
>>> anyone know of a 8 to 16 pin alternative (just square and triangle
>>> out) that won't break the bank.
>>> Thanks
>>> -Slackmeister
>> I see i have two unused NE566E's.
>
> Now all you need is a time machine to transport them back
> to 2016.
No, they're likely already there! The issue is getting the INFORMATION
regarding their availability to the OP!
Reply by Phil Hobbs●July 28, 20222022-07-28
Paul Badenhorst wrote:
> On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
>> I have benn trying to find a decent alternative to the LM566 VCO. It
>> does not seem to be sold anymore at reputable sellers and the ones on
>> EBay (from China) I don't trust to be authentic or unrecycled. Does
>> anyone know of a 8 to 16 pin alternative (just square and triangle
>> out) that won't break the bank.
>> Thanks
>> -Slackmeister
> I see i have two unused NE566E's.
>
Re: Google Groups
Welcome to Usenet (not Google Groups). This group is
sci.electronics.design, which is actually older than Google.
It's entirely unmoderated and unrestricted, except for the generally
accepted informal rules, known as *netiquette*.
Don't let Rob discourage you--c'mon and join the fun.
Re: NE566
The 566 is a really crappy oscillator. It's perfectly okay for a
junkbox project, of course--I've done lots worse things myself--but for
a real design there are many, much better choices nowadays.
On the simple end, the oscillator of a CD4046 will work as a very
wide-range VCO with a pretty linear tuning characteristic over about
100:1 in frequency, though the center frequency isn't that accurately
controlled by the RC time constant.
The 4046 has only a square-wave output, so if that's a worry one could
use one of many dual op amps. One section would be a Howland current
source driving an integration capacitor with its other end grounded, and
the other would be a Schmitt trigger controlling the polarity of the
Howland. That will be better than the 556, but of course needs a lot of
extra resistors. (On a PC board, one could make both the Howland and
the Schmitt using one 8x resistor array, so it wouldn't be that many
parts in real life.)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by legg●July 28, 20222022-07-28
On Wed, 27 Jul 2022 23:27:48 -0700 (PDT), Paul Badenhorst
<paulbpb@gmail.com> wrote:
>On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
>> I have benn trying to find a decent alternative to the LM566 VCO. It
>> does not seem to be sold anymore at reputable sellers and the ones on
>> EBay (from China) I don't trust to be authentic or unrecycled. Does
>> anyone know of a 8 to 16 pin alternative (just square and triangle
>> out) that won't break the bank.
>> Thanks
>> -Slackmeister
>I see i have two unused NE566E's.
Now all you need is a time machine to transport them back
to 2016.
RL
Reply by Paul Badenhorst●July 28, 20222022-07-28
On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
> I have benn trying to find a decent alternative to the LM566 VCO. It
> does not seem to be sold anymore at reputable sellers and the ones on
> EBay (from China) I don't trust to be authentic or unrecycled. Does
> anyone know of a 8 to 16 pin alternative (just square and triangle
> out) that won't break the bank.
> Thanks
> -Slackmeister
I see i have two unused NE566E's.
Reply by Paul Badenhorst●July 28, 20222022-07-28
On Friday, 19 August 2016 at 04:38:37 UTC+2, Kevin Glover wrote:
> I have benn trying to find a decent alternative to the LM566 VCO. It
> does not seem to be sold anymore at reputable sellers and the ones on
> EBay (from China) I don't trust to be authentic or unrecycled. Does
> anyone know of a 8 to 16 pin alternative (just square and triangle
> out) that won't break the bank.
> Thanks
> -Slackmeister
I have just seen your message. just thinking. Would it not be possible to use a LM565 's VCO. Would have to design a small board to fit the LM566 socket. If you could find them? also discontinued.
Reply by JW●August 20, 20162016-08-20
On Sat, 20 Aug 2016 06:34:03 -0700 Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in Message id:
<3tmgrb1bhivi4ck730lr7acnsunehb69so@4ax.com>:
>On Fri, 19 Aug 2016 23:25:23 -0400, Spehro Pefhany
><speffSNIP@interlogDOTyou.knowwhat> wrote:
>
>>On Thu, 18 Aug 2016 19:38:30 -0700, the renowned Kevin Glover
>><kevinfglover@yahoo.com> wrote:
>>
>>>I have benn trying to find a decent alternative to the LM566 VCO. It
>>>does not seem to be sold anymore at reputable sellers and the ones on
>>>EBay (from China) I don't trust to be authentic or unrecycled. Does
>>>anyone know of a 8 to 16 pin alternative (just square and triangle
>>>out) that won't break the bank.
>>>Thanks
>>>-Slackmeister
>>
>>I like the roll-your-own one with a single BJT or MOSFET and 1/2 an
>>LM324. Triangle out from the integrator and square wave output from
>>the comparator. You can shape the triangle wave into a facsimile of a
>>sine wave but that gets more complex or requires trimming.
>>
>>---sp
>
>That's sort of the way I'd do it... except I'd use a package of
>LM339's and make good triangles, and linear frequency versus voltage,
>with current mirror control.
>
>You can simply add current mirrors to a 555 and attain the same thing
>more simply... but it's forbidden to even mention a 555 Timer on this
>newsgroup >:-}
That's complete BS. ;)
Reply by Jim Thompson●August 20, 20162016-08-20
On Fri, 19 Aug 2016 23:25:23 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:
>On Thu, 18 Aug 2016 19:38:30 -0700, the renowned Kevin Glover
><kevinfglover@yahoo.com> wrote:
>
>>I have benn trying to find a decent alternative to the LM566 VCO. It
>>does not seem to be sold anymore at reputable sellers and the ones on
>>EBay (from China) I don't trust to be authentic or unrecycled. Does
>>anyone know of a 8 to 16 pin alternative (just square and triangle
>>out) that won't break the bank.
>>Thanks
>>-Slackmeister
>
>I like the roll-your-own one with a single BJT or MOSFET and 1/2 an
>LM324. Triangle out from the integrator and square wave output from
>the comparator. You can shape the triangle wave into a facsimile of a
>sine wave but that gets more complex or requires trimming.
>
>---sp
That's sort of the way I'd do it... except I'd use a package of
LM339's and make good triangles, and linear frequency versus voltage,
with current mirror control.
You can simply add current mirrors to a 555 and attain the same thing
more simply... but it's forbidden to even mention a 555 Timer on this
newsgroup >:-}
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I'm looking for work... see my website.
Reply by P E Schoen●August 20, 20162016-08-20
"Kevin Glover" wrote in message
news:h1scrbh3b2khj2hpfnbfijj1vr6edv9h6h@4ax.com...
> I have benn trying to find a decent alternative to the LM566 VCO. It does
> not seem to be sold anymore at reputable sellers and the ones on EBay
> (from China) I don't trust to be authentic or unrecycled. Does anyone know
> of a 8 to 16 pin alternative (just square and triangle out) that won't
> break the bank.
> I have benn trying to find a decent alternative to the LM566 VCO. It
> does not seem to be sold anymore at reputable sellers and the ones on
> EBay (from China) I don't trust to be authentic or unrecycled. Does
> anyone know of a 8 to 16 pin alternative (just square and triangle
> out) that won't break the bank.