Favorite precision rectifier
Tim Williams
I need something good for sines and triangles of a volt or so, up to 100kHz
or so. I'm looking at this
http://webpages.charter.net/dawill/Images/Precision_FWR.gif
but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
zero crossing. Eww.
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
lang...@fonz.dk
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up to 100kHz
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> zero crossing. Eww.
>
> Tim
>
isn't this the standard from some AD appnote:
http://www.play-hookey.com/analog/full-wave_rectifier.html
-Lasse
John Larkin
<tmor...@charter.net> wrote:
>What's your favorite full wave precision rectifier circuit?
Firmware.
John
Jim Thompson
<tmor...@charter.net> wrote:
>What's your favorite full wave precision rectifier circuit?
>
>I need something good for sines and triangles of a volt or so, up to 100kHz
>or so. I'm looking at this
>http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>zero crossing. Eww.
>
>Tim
My favorite:
http://analog-innovations.com/SED/FullWaveRectifier.pdf
I've been using it since the mid '80's, first for a 400KHz
application, back when OpAmp GBW wasn't nearly as good as they are
now.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Isn't the definition of "totalitarian" when the government owns
significant manufacturing; and controls the major media outlets?
John Larkin
<tmor...@charter.net> wrote:
>What's your favorite full wave precision rectifier circuit?
OK, all analog: use a comparator to sense the sign of the input, and
then switch a +1/-1 gain stage.
John
Phil Hobbs
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up to 100kHz
> or so. I'm looking at this
> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> zero crossing. Eww.
>
> Tim
>
I usually use a Gilbert cell driven by a comparator.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
Tim Williams
news:wuadnYLNzdkcXafX...@supernews.com...
> I usually use a Gilbert cell driven by a comparator.
Uselessly overcomplicated.
Has a certain elegance about it though. Breaking it down to its components,
you have a stacked differential amplifier (the mixer) and a high gain
differential amplifier (the comparator), which should have a differential
output to drive the mixer to saturation (or use diode steering). But that's
none other than taking signal x, amplifying the piss out of it to get
100,000x clamped to the supply rails, which is essentially the sign function
(in this case, +1 if x > epsilon, -1 if x < epsilon, x/epsilon if |x| <
espilon). So it generates sign(x) * x, which is another way of writing |x|.
Neato.
Jim Thompson
<tmor...@charter.net> wrote:
>"Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
>news:wuadnYLNzdkcXafX...@supernews.com...
>> I usually use a Gilbert cell driven by a comparator.
>
>Uselessly overcomplicated.
>
>Has a certain elegance about it though. Breaking it down to its components,
>you have a stacked differential amplifier (the mixer) and a high gain
>differential amplifier (the comparator), which should have a differential
>output to drive the mixer to saturation (or use diode steering). But that's
>none other than taking signal x, amplifying the piss out of it to get
>100,000x clamped to the supply rails, which is essentially the sign function
>(in this case, +1 if x > epsilon, -1 if x < epsilon, x/epsilon if |x| <
>espilon). So it generates sign(x) * x, which is another way of writing |x|.
>Neato.
>
>Tim
Often the only way when you have 500MHz signals to deal with.
Joel Koltner
news:2uA_l.32476$gz5....@newsfe07.iad...
> "Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
> news:wuadnYLNzdkcXafX...@supernews.com...
>> I usually use a Gilbert cell driven by a comparator.
> Uselessly overcomplicated.
If you're doing a discrete (not ICs) design, it's arguably a lot simpler than
building the equivalent op-amp-style circuit... we're talking, what, no more
than a dozen transistors here (current sources included), right?
I sense a "fewest number of transistors absolute value circuit" design
challenge coming on. :-)
MooseFET
wrote:
> "Tim Williams" <tmoran...@charter.net> wrote in message
>
> news:2uA_l.32476$gz5....@newsfe07.iad...
>
> > "Phil Hobbs" <pcdhSpamMeSensel...@electrooptical.net> wrote in message
> >news:wuadnYLNzdkcXafX...@supernews.com...
> >> I usually use a Gilbert cell driven by a comparator.
> > Uselessly overcomplicated.
>
> If you're doing a discrete (not ICs) design, it's arguably a lot simpler than
> building the equivalent op-amp-style circuit... we're talking, what, no more
> than a dozen transistors here (current sources included), right?
>
> I sense a "fewest number of transistors absolute value circuit" design
> challenge coming on. :-)
!
[R]10K
!
+-------Vout
!/
AC IN------!
!\e 2N3904
!
[R]10K
!
-10V
What do I win?
Jim Thompson
That ought to produce some real crap designs ;-)
George Herold
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up to 100kHz
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> zero crossing. Eww.
>
> Tim
>
> --
> Deep Friar: a very philosophical monk.
> Website:http://webpages.charter.net/dawill/tmoranwms
H&H AoE. not sure the chapter or page. You add the inverse to the
half wave rectified signal. (or something like that) through an
opamp.
I'm pretty sure they didn't invent it but that's where I saw it
first.
George H.
George Herold
Web-Site.com> wrote:
> On Thu, 18 Jun 2009 16:00:50 -0500, "Tim Williams"
>
> >What's your favorite full wave precision rectifier circuit?
>
> >I need something good for sines and triangles of a volt or so, up to 100kHz
> >or so. I'm looking at this
> >http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> >but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> >zero crossing. Eww.
>
> >Tim
>
> My favorite:
>
> http://analog-innovations.com/SED/FullWaveRectifier.pdf
>
> I've been using it since the mid '80's, first for a 400KHz
> application, back when OpAmp GBW wasn't nearly as good as they are
> now.
>
> ...Jim Thompson
> --
> | James E.Thompson, P.E. | mens |
> | Analog Innovations, Inc. | et |
> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
> | Phoenix, Arizona 85048 Skype: Contacts Only | |
> | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
>
> Isn't the definition of "totalitarian" when the government owns
> significant manufacturing; and controls the major media outlets?
Hmm, I haven't seen that before. I'll give it a whirl.
Thanks,
George H.
George Herold
Phil,
Do you 'roll your own' Gilbert cell?.
Tim,
I'm using an AD multiplier chip, part number 'unsure' (sorry I'm at
home with dial-up and it's too painful to go searching the web.)
That's claimed to be good up to 10MHz. It works great for detecting
noise up to 100kHz. (and beyond)
George H.
Phil Hobbs
> "Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
> news:wuadnYLNzdkcXafX...@supernews.com...
>> I usually use a Gilbert cell driven by a comparator.
>
> Uselessly overcomplicated.
>
> Has a certain elegance about it though. Breaking it down to its components,
> you have a stacked differential amplifier (the mixer) and a high gain
> differential amplifier (the comparator), which should have a differential
> output to drive the mixer to saturation (or use diode steering). But that's
> none other than taking signal x, amplifying the piss out of it to get
> 100,000x clamped to the supply rails, which is essentially the sign function
> (in this case, +1 if x > epsilon, -1 if x < epsilon, x/epsilon if |x| <
> espilon). So it generates sign(x) * x, which is another way of writing |x|.
> Neato.
>
> Tim
>
It's about 25 cents worth of parts, smaller than a dime, and works
great. Useless is in the eye of the beholder, I suppose.
Phil Hobbs
> On Jun 18, 6:32 pm, Phil Hobbs
> <pcdhSpamMeSensel...@electrooptical.net> wrote:
>> Tim Williams wrote:
>>> What's your favorite full wave precision rectifier circuit?
>>> I need something good for sines and triangles of a volt or so, up to 100kHz
>>> or so. I'm looking at this
>>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>>> zero crossing. Eww.
>>> Tim
>> I usually use a Gilbert cell driven by a comparator.
>>
>
> Phil,
> Do you 'roll your own' Gilbert cell?.
Generally I use an array, e.g. an MC1496.
Wimpie
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up to 100kHz
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> zero crossing. Eww.
>
> Tim
>
> --
> Deep Friar: a very philosophical monk.
> Website:http://webpages.charter.net/dawill/tmoranwms
Hello Tim,
What relative input range is required and how good it must be
(linearity, offset drift, etc)?
The larger the relative input range, the larger the gain must be in
case of a feedback approach.
Best regards,
Wim
PA3DJS
www.tetech.nl
remove first three letters of alphabet in the PM
Jim Thompson
<pcdhSpamM...@electrooptical.net> wrote:
>George Herold wrote:
>> On Jun 18, 6:32 pm, Phil Hobbs
>> <pcdhSpamMeSensel...@electrooptical.net> wrote:
>>> Tim Williams wrote:
>>>> What's your favorite full wave precision rectifier circuit?
>>>> I need something good for sines and triangles of a volt or so, up to 100kHz
>>>> or so. I'm looking at this
>>>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>>>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>>>> zero crossing. Eww.
>>>> Tim
>>> I usually use a Gilbert cell driven by a comparator.
>>>
>
>>
>> Phil,
>> Do you 'roll your own' Gilbert cell?.
>
>Generally I use an array, e.g. an MC1496.
>
>Cheers
>
>Phil Hobbs
An MC1496 is NOT an array... it's the real deal ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Jim Thompson
<pcdhSpamM...@electrooptical.net> wrote:
>Tim Williams wrote:
>> What's your favorite full wave precision rectifier circuit?
>>
>> I need something good for sines and triangles of a volt or so, up to 100kHz
>> or so. I'm looking at this
>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>> zero crossing. Eww.
>>
>> Tim
>>
>
>I usually use a Gilbert cell driven by a comparator.
>
>Cheers
>
>Phil Hobbs
Like-a dis...
http://analog-innovations.com/SED/AM-Demodulator-MC1496.pdf
George Herold
>
> - Show quoted text -
Cool, I use the AD630 as a 'lockin' chip. Someone told me that was
what I should use and I never bothered lokking for other
demodulators. So the MC1496 is 150 times faster and 1/20 the cost.
What's the down side? The carrier feed through numbers look a bit
scary. 20 - 200 mV with a sqaure wave if the offset isn't adjusted.
George H.
Joel Koltner
news:a66eca9e-4c85-4dbc...@c19g2000prh.googlegroups.com...
" +10V
!
[R]10K
!
+-------Vout
!/
AC IN------!
!\e 2N3904
!
[R]10K
!
-10V
What do I win?"
Sure doesn't look like a precision rectifier to me...
Winner will get... gift certificate for a Dairy Queen brownie batter blizzard?
Phil Hobbs
> On Fri, 19 Jun 2009 05:45:46 -0400, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
>> George Herold wrote:
>>> On Jun 18, 6:32 pm, Phil Hobbs
>>> <pcdhSpamMeSensel...@electrooptical.net> wrote:
>>>> Tim Williams wrote:
>>>>> What's your favorite full wave precision rectifier circuit?
>>>>> I need something good for sines and triangles of a volt or so, up to 100kHz
>>>>> or so. I'm looking at this
>>>>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>>>>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>>>>> zero crossing. Eww.
>>>>> Tim
>>>> I usually use a Gilbert cell driven by a comparator.
>>>>
>>> Phil,
>>> Do you 'roll your own' Gilbert cell?.
>> Generally I use an array, e.g. an MC1496.
>>
>> Cheers
>>
>> Phil Hobbs
>
> An MC1496 is NOT an array... it's the real deal ;-)
>
> ...Jim Thompson
Yep, but it's becoming hard to get.
Phil Hobbs
between two points fairly far from ground. If you're building a
lock-in, one good method for getting round this is to use a single cap
between the (collector) outputs, and a switched-capacitor block to
transfer the difference voltage down to ground. Since there's only one
cap, there's no opportunity for the two sides to have different
bandwidths and phase shifts, which helps. I used three of those in a
little non-contact head tracker about 15 years ago. Nice gizmo.
Jon Kirwan
<gghe...@gmail.com> wrote:
>So the MC1496 is 150 times faster and 1/20 the cost.
Cripes, if you need a few they are 3 cents each?
US$70+ship buys 2500 SOIC on tape/reel?
About the cost of a cheap BJT.
Jon
Michael A. Terrell
Phil Hobbs wrote:
>
> George Herold wrote:
> > On Jun 18, 6:32 pm, Phil Hobbs
> > <pcdhSpamMeSensel...@electrooptical.net> wrote:
> >> Tim Williams wrote:
> >>> What's your favorite full wave precision rectifier circuit?
> >>> I need something good for sines and triangles of a volt or so, up to 100kHz
> >>> or so. I'm looking at this
> >>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> >>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> >>> zero crossing. Eww.
> >>> Tim
> >> I usually use a Gilbert cell driven by a comparator.
> >>
>
> >
> > Phil,
> > Do you 'roll your own' Gilbert cell?.
>
> Generally I use an array, e.g. an MC1496.
TO-5 or DIP? ;-)
--
You can't have a sense of humor, if you have no sense!
Phil Hobbs
I've used PDIPs and SO-14s. 2N3904s were invented a long time ago too.
Cheers
Robert Baer
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up to 100kHz
> or so. I'm looking at this
> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> zero crossing. Eww.
>
> Tim
>
stra...@yahoo.com
> What's your favorite full wave precision rectifier circuit?
>
> I need something good for sines and triangles of a volt or so, up
to 100kHz
> but it has an ugly ~1us propagation delay, resulting in a 200-400mV
step at
> zero crossing. Eww.
>
> Tim
>
> Deep Friar: a very philosophical monk.
> Website:http://webpages.charter.net/dawill/tmoranwms
See page 19, figure 12 of the Analog Devices AD8036 datasheet.
http://www.analog.com/static/imported-files/data_sheets/AD8036_8037.pdf
G²
Tim Williams
>> An MC1496 is NOT an array... it's the real deal ;-)
>
AAMOF, I have a few LM1496S (TO-5 style!) in my parts box. Removed from
some TV modulator equipment. Some CA3026s and TL442s, too.
Tim Williams
Sounds horrendously expensive (well, of course it is, it's AD).
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
<stra...@yahoo.com> wrote in message
news:2eb62fb0-ac6b-4ec2...@s21g2000vbb.googlegroups.com...
http://www.analog.com/static/imported-files/data_sheets/AD8036_8037.pdf
G�
Jan Panteltje
stra...@yahoo.com wrote in
<2eb62fb0-ac6b-4ec2...@s21g2000vbb.googlegroups.com>:
>See page 19, figure 12 of the Analog Devices AD8036 datasheet.
>
>http://www.analog.com/static/imported-files/data_sheets/AD8036_8037.pdf
Nice chip :-)
Clifford Heath
> Jim Thompson wrote:
>> An MC1496 is NOT an array... it's the real deal ;-)
I see it listed at 12 of the 21 distributors indexed by
http://findchips.com - but none at 25c - is that where
you're encountering difficulty? Mind you, 35c doesn't
seem too much to pay.
Phil Hobbs
It isn't too much, but when these old chips start to increase in price,
you have to start being careful, IME. Of course it may be that the
rest of the world discovered their extreme usefulness and drove up the
price.
Jim Thompson
<tmor...@charter.net> wrote:
>Intristing.
>
>Sounds horrendously expensive (well, of course it is, it's AD).
>
>Tim
>
>G?
And single source, _top_poster_ with misplaced separator :-(
Jim Thompson
<tmor...@charter.net> wrote:
>What's your favorite full wave precision rectifier circuit?
>
>I need something good for sines and triangles of a volt or so, up to 100kHz
>or so. I'm looking at this
>http://webpages.charter.net/dawill/Images/Precision_FWR.gif
>but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
>zero crossing. Eww.
>
>Tim
If you had simulated that circuit you would have seen that
"undershoot".
If you had simulated my submission, you'd still see some "undershoot",
though significantly less.
There's a specific reason for that. Study both versions and try to
discern the difference... Left as an exercise for the student ;-)
George Herold
Thanks Phil, I’ve no foreseeable project requiring a lockin, but was
only asking out of interest.
“>Since there's only one
> cap, there's no opportunity for the two sides to have different
> bandwidths and phase shifts, which helps.”
I’d never thought of the uniform bandwidth and phase shift advantage
of switched capacitors. (Versus the paired RC’s I’ve used and always
lamented the different time constants.)
George H.
Spehro Pefhany
Seems to be a mistake- shows 0.38 above as price in multiples of 2500
(sometimes). Digikey 0.383, Avnet 0.364 in 1-reel lots.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
George Herold
Web-Site.com> wrote:
> On Thu, 18 Jun 2009 18:32:32 -0400, Phil Hobbs
>
>
>
>
>
> <pcdhSpamMeSensel...@electrooptical.net> wrote:
> >Tim Williams wrote:
> >> What's your favorite full wave precision rectifier circuit?
>
> >> I need something good for sines and triangles of a volt or so, up to 100kHz
> >> or so. I'm looking at this
> >>http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> >> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> >> zero crossing. Eww.
>
> >> Tim
>
> >I usually use a Gilbert cell driven by a comparator.
>
> >Cheers
>
> >Phil Hobbs
>
> Like-a dis...
>
> http://analog-innovations.com/SED/AM-Demodulator-MC1496.pdf
>
> ...Jim Thompson
> --
> | James E.Thompson, P.E. | mens |
> | Analog Innovations, Inc. | et |
> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
> | Phoenix, Arizona 85048 Skype: Contacts Only | |
> | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
>
> Isn't the definition of "totalitarian" when the government owns
>
> - Show quoted text -
Thanks Jim! I'll include a few in the next order I place.
George H.
Tim Williams
message news:2kvp359lrurvvckpt...@4ax.com...
> And single source, _top_poster_ with misplaced separator :-(
Mmm?
stratus' post didn't autoindent for some reason. I can't be bothered to
edit it. Short, general comments go at the top. Easy to understand. My
sig was correctly placed, and correctly formatted. That leaves one thing,
top poster prejudice. In that case, go fuck off and die, I could care less.
Tim Williams
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
"Jim Thompson" <To-Email-Use-Th...@My-Web-Site.com> wrote in
message news:ep6q355aec64m1luo...@4ax.com...
Jim Thompson
<tmor...@charter.net> wrote:
>Er well, that's fairly obvious. It goes through two op-amps.
>
>Tim
>
Er well, that's not why, and you have no clue about circuits.
Further exhibits: Your stupid top posting AND your ignorant/improper
placement of hyphen-hyphen-space.
Sheeeeesh!
**>--
Jon Kirwan
<spef...@interlogDOTyou.knowwhat> wrote:
>On Fri, 19 Jun 2009 22:28:11 GMT, the renowned Jon Kirwan
><jo...@infinitefactors.org> wrote:
>
>>On Fri, 19 Jun 2009 09:50:14 -0700 (PDT), George Herold
>><gghe...@gmail.com> wrote:
>>
>>>So the MC1496 is 150 times faster and 1/20 the cost.
>>
>>Cripes, if you need a few they are 3 cents each?
>>
>>
>>http://app.arrownac.com/aws/pg_webc/0,1086,,00.html?application=SEARCH&appid=nac&event=1020&docid=685557S2902716N5210
>>
>>US$70+ship buys 2500 SOIC on tape/reel?
>>
>>About the cost of a cheap BJT.
>>
>>Jon
>
>Seems to be a mistake- shows 0.38 above as price in multiples of 2500
>(sometimes). Digikey 0.383, Avnet 0.364 in 1-reel lots.
Yeah. However, I tried an order of 2500 just on a lark. (I am
willing to spent $70.) I got this confirmation:
Subject: Order Request Accepted
From: "Arrow Electronics Inc." <onlin...@arrow.com>
Thank you for placing an online order with Arrow Electronics,
Inc. Your Order #: xxxxxx
Your order request, placed on xxxxxxxx, has been received.
Please save this email or print it out; it will serve as the
detailed STATEMENT of charges posted to your credit card. An
invoice will not be mailed with your order so please retain a
copy of this email for your records.
Item Qty Part/Description/Supplier Price
1 2500 MC1496DR2/ON Semiconductor $0.03
Subtotal: $70.50
Applicable Sales Tax: $0.00
Shipping/Energy Surcharge: $8.99
Total: US$79.49
We shall see if the reel arrives.
Jon
MooseFET
wrote:
> "MooseFET" <kensm...@rahul.net> wrote in message
>
> news:a66eca9e-4c85-4dbc...@c19g2000prh.googlegroups.com...
> " +10V
> !
> [R]10K
> !
> +-------Vout
> !/
> AC IN------!
> !\e 2N3904
> !
> [R]10K
> !
> -10V
>
> What do I win?"
>
> Sure doesn't look like a precision rectifier to me...
It depends a lot on how you define "precision".
It does better than a simple diode.
Michael A. Terrell
Phil Hobbs wrote:
>
> Michael A. Terrell wrote:
> > Phil Hobbs wrote:
> >> George Herold wrote:
> >>> On Jun 18, 6:32 pm, Phil Hobbs
> >>> <pcdhSpamMeSensel...@electrooptical.net> wrote:
> >>>> Tim Williams wrote:
> >>>>> What's your favorite full wave precision rectifier circuit?
> >>>>> I need something good for sines and triangles of a volt or so, up to 100kHz
> >>>>> or so. I'm looking at this
> >>>>> http://webpages.charter.net/dawill/Images/Precision_FWR.gif
> >>>>> but it has an ugly ~1us propagation delay, resulting in a 200-400mV step at
> >>>>> zero crossing. Eww.
> >>>>> Tim
> >>>> I usually use a Gilbert cell driven by a comparator.
> >>>>
> >>> Phil,
> >>> Do you 'roll your own' Gilbert cell?.
> >> Generally I use an array, e.g. an MC1496.
> >
> >
> > TO-5 or DIP? ;-)
>
> I've used PDIPs and SO-14s. 2N3904s were invented a long time ago too.
I've used the MC1496 in TO-5, Dip and SOIC over the years. I
preferred the MC1596 but it was discontinued over ten years ago.
Spehro Pefhany
>G�
I recently used something like that for a low-noise sensor simulator
which had to square the high frequency modulation signal. Worked fine.
Jon Kirwan
><snip>
>We shall see if the reel arrives.
Yup. 2500 of the beasties _DID_ arrive. All nicely done up in a full
reel. Cost me 3.1796 cents each after shipping costs are included.
So, anyone looking for a supplier of cheap 14-pin SOIC MC1496's? ;)
Jon
JosephKK
So how to handle a us$5 transaction and how much of that gets eaten up
in postage?
Jon Kirwan
I've no idea. I've never really been in the business of selling parts
and am not really interested in starting, this late in life. ;) I
give them away, as a rule. But locally, to students and schools. (I
still have almost 26000 TO-92 PN3904's, for example, bought at _well_
less than a penny each. I stock up on common parts when I can find a
good deal on them and give to schools that seem willing to take a shot
at using them.)
I gambled on these because they seemed so cheap, I was curious because
Spehro wondered if it may be a mistake, I don't fret a few ten spots
here and there just on a lark like this, and because the part
schematic seems more broadly useful for stuff I play with than I'd
first imagined. I actually may use some. By the way, this now puts
me in the market for a book called "2501 wild and crazy uses for the
MC1496!"
If you are serious, I'll ask the post office about "issues." But I
suspect that since these are in easily cut strips and don't weigh that
much, I might be able to send them pretty cheaply. An envelope might
work. Just today, I watched as a postal worker used a 3x5 card to
"wrap up" a stamp I was sending to someone, folding over edges in ways
that would make you cringe and then just stuffing it into the standard
stamped envelope I had handy. If that works through their ZMT
machines, I have to guess something simple like strips of tiny parts
stuck between two 3x5 cards in an envelop should work at 44 cents.
Worst that can happen is the postman stomps on them, I suppose. It'd
probably cost me more to worry about getting paid. So I'm open to
suggestions. My email is open and works. Perhaps you have something
interesting to offer in exchange? Spare resistors, even?
Jon