What limits noise in voltage regulators?

Use a non-breaking space. It's only a matter of holding down a modifier key on old Macs (I don't know what is involved on modern ones or on PCs).

--
~ Liz Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

It's worse than that. Google just strips out all the spaces after the first one, so that information is actually destroyed.

Otherwise that scrooched thing George posted would have rendered properly in a real newsreader.

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.net 
http://hobbs-eo.com

Right, I cut and pasted into text editor... with hopes of recovering the pic by just adding leading spaces one each line... But no! All 'extra' spaces have been taken out. usernet ascii art ruined by google. If someone knew someone.... I sent feedback saying I wanted the 'show original' option back. (no response from gg.) George h.

59 AM UTC-5, Phil Hobbs wrote:

n cascade. There's no feedback to speak of. For a

wo-stage cap multiplier, you just go

Q2

| \ A \ A |

o CCC | | |

| | | |

CCC CCC CCC CCCC alpo

GND GND

u send the above ascii art to my email?

it hard to de-scramble the above. Google takes out the sp aces...

e sense... but...

he ascii art in google groups?

This is a ascii schema tic test... It assumes Unicode works in GG.

In one cas e I replaced all spaces (U+0020 SPACE [SP]) with a U+00D7 MULTIPLICATION SIGN, as a dummy, that hopefully does not get stripped. In the second case I tried someone's sugge stion of using a non breaking space... in case the Google Shiva does not see it as white space to be minimized.

ll non-breaking space U+00A0 NO-BREAK SPACE [NBSP]

7 AM UTC-8, George Herold wrote:

t go

--* *--------* *----*--0

giant CCC ------ ------ |

| | |

CCC CCC CCCC alpo

GND GND

ld you send the above ascii art to my email?

found it hard to de-scramble the above. Google takes out the spaces...

cture make sense... but...

o recover the ascii art in google groups?

cii schematic test... It assumes Unicode works in GG.

) with a U+00D7 MULTIPLICATION SIGN, as a dummy, that hop efully does not get stripped. In the second case I tried someone's suggestion of using a non breaking space... in case the Google Shiva does not see it as white space to b e minimized.

+00A0 NO-BREAK SPACE [NBSP]

?? 50.000000 ?

pF

frequency

z

????

? ???? 17.132488 pF 88.208190 MHz

8.891234 pF

es. frequency

11 ????C???? 54.368883 pF

??

???? 47.125095 pF 81.208866 MHz

43591 pF 17 ????R???? 74.078142 ?

Either way

7 AM UTC-8, George Herold wrote:

t go

--* *--------* *----*--0

giant CCC ------ ------ |

| | |

CCC CCC CCCC alpo

GND GND

ld you send the above ascii art to my email?

found it hard to de-scramble the above. Google takes out the spaces...

cture make sense... but...

o recover the ascii art in google groups?

cii schematic test... It assumes Unicode works in GG.

) with a U+00D7 MULTIPLICATION SIGN, as a dummy, that hop efully does not get stripped. In the second case I tried someone's suggestion of using a non breaking space... in case the Google Shiva does not see it as white space to b e minimized.

+00A0 NO-BREAK SPACE [NBSP]

?? 50.000000 ?

pF

frequency

z

????

? ???? 17.132488 pF 88.208190 MHz

8.891234 pF

es. frequency

11 ????C???? 54.368883 pF

??

???? 47.125095 pF 81.208866 MHz

43591 pF 17 ????R???? 74.078142 ?

Hi Simon, The above does look better when copied and pasted into a text editor... I can copy it back, it looks the same.

I think it's wrong to make ascii art fit google.

Geo

ce U+00A0 NO-BREAK SPACE [NBSP] 1 ????R??? ??? 50.000000 ? 3 ????C???? 25.

305273 pF ? ???? 4 ? L C 131.9 70860 nH res.frequency ? ???? 16.56201 5 pF 107.652600 MHz 5 ????C???? 42.45 2992 pF ? ???? 6 ? L C 190.021 181 nH res.frequency ? ???? 17.132488 pF 88.208190 MHz 8 ? C 48.891234 pF 9 ?? ???L?C??? 266.819370 nH res. frequency ? ? 190.531166 pF 22.321760 MHz 11 ???? C???? 54.368883 pF ? ???? 12 ? L C 81.504415 nH res.frequency ? ? ??? 47.125095 pF 81.208866 MHz 14 ? C 91.843591 pF 15 ????C???? 4.580406 pF

17 ????R???? 74.078142 ?

hah hah. I agree with your principle. God Google doesn't care about our principles any more than our spaces.

This will cause problems for those readers using newsreaders not supporting Unicode.

Since the file is transmitted as MIME, it is then possible to extract it to a file and view it with Notepad on any Windows NT an later computers.

A simple solution would be to use ordinary periods instead of spaces.

A better solution is to put it in LTspice. Zip the ASC and PLT files and upload to

--
The best designs are no accident - sw

Which requires installing LTspice on the system in order to follow the discussion.

An LTspice prerequisite mostly limits your communication to a subset of readers who already use LTspice. Worse, you only reach a subset of LTspice users with enough gumption to actually download and unzip multiple zip files, plural. It demands a lot from readers of ephemeral online conversations.

The easier you make it for your readers, the more people hear you. The best way to communicate online is to speak through a webpage hosted on your own website.

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

On Tuesday, February 2, 2021 at 9:31:20 PM UTC-8, snipped-for-privacy@downunder.com wr ote:

IPLICATION SIGN, as a dummy, that hopefully does not get stripped. In the s econd case I tried someone's suggestion of using a non breaking space... in case the Google Shiva does not see it as white space to be minimized.

Periods are definitely used in some "ASCII" SCH. So, use of a period would create an escape problem. Escape problems are much less probable w/ Unicode

readers.

Unicode has been around long enough to rule out usage of archaic non-suppor tive readers. Google groups apparently supports Unicode. HTML standards acc ommodate Unicode to the extent needed here, as do modern browsers.

[...]

An improvement is to use a constant current source for the first stage instead of an emitter follower. An emitter follower gives zero attenuation at low frequencies due to the low impedance driving the increasing impedance of the filter capacitor.

A constant current source is a high impedance, and gives good attenutation down to low frequency. The example below gives around -28dB at 10 Hz, where the emitter follower has to go aboe 300 Hz for the same attenuation.

The constant current source also gives a respectable -180dB attenuation between 100 KHz and 2 MHz. The attenuation at higher frequencies depends on the quality of the bypass capacitors, and it is probably a good idea to add ceramics in parallel.

--
The best designs are no accident - sw

What on earth are you doing messing around with electronics without using LTspice? How do you run an ASCII file?

SPICE has a huge learning curve, I'll grant you that. But it opens your eyes to insights about electronics that you can never get with pencil and paper.

Many have objected to the use of LTspice. Bob Pease, Winfield Hill, and even some of the leaders of this newsgroup. But when they learned what LTspice could do, they gave up on the old methods and embraced the use of LTspice completely.

There is no way to verify the validity of an ASCII circuit. You have to build it, and have all the equipment needed to test it, or convert it to LTspice and simulate it. It turns out the LTspice route is far simpler, faster, and gives far more information than you could ever get on the bench.

You can quickly determine if a design is worth spending the time building, or if it is hopeless and should be discarded.

Or what it needs to fix it and make it a valuable addition to your repertoire.

Once you have analyzed a circuit in LTspice, the next step is to actually build it and see how well it works.

But there are many traps and pitfalls in bench work. You could have miswires, inadvertent solder bridges, shorts, faulty components, crosstalk, parasitic oscillations, poor RF grounding, and a host of other issues that bedevil experiments.

One of the first problems to solve is how to mount the components. Most experienced people recommend against using the solderless prototyping boards, shown here:

2016.html

These boards suffer from poor connections, crosstalk, stray capacitance, poor RF grounding, excessive inductance in the connections, unreliability, poor layout capability, unsuitabililty for SMD components, and many other issues. You end up spending all your time trying to solve problems that should never exist in the first place.

Perfboard is an improvement over solderless breadboards, but suffer from many of the same problems:

The next step up is dead bug and air wiring, favored by some demented inhabitants of this newsgroup. Here, the circuit is built on a copperclad ground plane (+1), and the ic's are glued upside-down on the copperclad.

The obvious problem is you cannot read the information on the top of the ic that tells you what kind it is. Six months later when you have forgotten, you cannot identify which ic is which, or how the circuit is supposed to work.

The components are air wired using the ic leads and each other for support.

Air wiring is great for the shortest leads possible and the lowest stray capacity to ground, but is impractical for SMD components. It is also fragile and delicate, and the weight of a single scope probe could cause short circuits.

Live bug prototyping is identical to dead bug, except the ic's are mounted rightside up on the ground plane so you can read the device information printed on the top.

Many prople including myself favor the Manhattan style of prototyping. There are many examples on the web such as

construction/

manhattan/

Manhattan style may give higher stray capacity and longer leads than some other methods, which can limit its use to frequencies below 1 Ghz. But it is a solid technique and deserves consideration in your next project.

In all these methods, LTspice can tell you not only if a circuit is worth building in the first place, and how it is supposed to work. This is invaluable in bench testing, where you could have any of a host of problems discussed above trying to build the circuit in real life.

So give up on ASCII art, and join the mainstream of electronic design and use. Load LTspice and learn to love it as so many others have done!

There are many, many articles and YouTube videos on how to use LTspice. One place to start is the LTwiki at

Another very useful group is the Yahoo page in groups.io:

And don't forget to check out the LTspice videos on Youtube.

Finally, there is the occasional post here in SED. So keep your eyes open for ASC files and give them a try.

--
The best designs are no accident - sw

[...]

Once you have graduated to copperclad for the excellent ground plane, clean it and spray with clear acrylic spray. This protects it against discoloration and fingrprints. You can solder through the coating.

Here is an example, but you can probably find a can in any hardware store:

Krylon Spray protects clear finish

$11.99

Finally, do not cut the ground plane unless you have a clear idea of what will happen. This can force ground currents to go places you do not want them to go, and it increases the impedance between points that increases the noise.

--
The best designs are no accident - sw

A constant current source has infinite impedance, which ISTM would be quite unlikely to improve a voltage-stabilization device.

Requires a sign-in.

I use cap multipliers a lot, and they work great. You can put them inside an op amp loop with split feedback if you want better low frequency ripple rejection--the amp can be powered off the cap multiplier's output to avoid its crappy HF CMR screwing everything up.

In a positive switching regulator circuit, you can even use the split-feedback trick to put the cap multiplier inside the regulator's feedback loop. You do have to watch the sneak path via the series RC, of course, but it's fine for light-duty use such as op amp rails.

Op amps have good CMR at LF but much less at HF, which makes cap multipliers the natural complement.

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.net 
http://hobbs-eo.com

If you mean your humble servant, that's a canard. I've used simulation routinely for years and years, and once spent a year of my life writing one that I needed but couldn't buy. However, I use circuit simulation almost exclusively for discrete circuitry since nearly all board-level SPICE models suck eggs.

Of course there is. You don't need a simulator to discuss architecture and topology, or to estimate how hot things will get, or figure out what effects are going to limit its performance. What GBW and slew rate do I need? How many bits in this digitizer? How clean do the rails need to be?

A lot of that gets done standing in front of a white board with no computers or soldering irons in sight.

The same white board is also good for optical / mechanical / software architecture and topology, often in the same session as the electronics.

Once you've figured out what you're going to build, you make the tradeoffs and do the detailed designs. Some of that will need to be simulated, and usually some bits breadboarded as well.

As Kipling's shipwrecked mariner said to the Whale, "Not so, but far otherwise." It'll give you as many plots as you like, true, but zero clues as to how well they match reality. Chip simulations based on foundry models can be very good indeed, but board level ones are a mixed bag, to put it kindly.

But not what to replace it with.

The simulator will not tell you that. You can think at the keyboard, the way most of us write, but the simulator doesn't design your circuit any more than Notepad will write your love letter.

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.net 
http://hobbs-eo.com

+1. You need a few strategically-placed solder blobs for probe grounds. +1 again. Wow, we're up to agreeing about a quarter of the time! ;)

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.net 
http://hobbs-eo.com

Use gold plated FR4.

(and use Dropbox)