AoE x-Chapters - 1x.1 Wire-&-Connectors

[Winfield Hill]

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1


--
Thanks,
- Win

 

[John Larkin]

On 5 Aug 2019 05:32:08 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Wonderful stuff.

It's impressive how hard it is to shield low frequency AC mag fields.

As far as copper foil resistance goes, I just remember, for 1 oz,


1 square of copper is 0.5 mohms and 70 K/W.


but when you ask for 1 oz you rarely get 1 oz.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Randy Day]

Sorry, Win's original post dropped off my reader.

P.15, second column, discussing Helmholtz coils:

"driven with an ac current of 2App"

I found the '2App' confusing for a bit;
would '2A p-p' be clearer?

 

[George Herold]

On Monday, August 5, 2019 at 11:26:37 AM UTC-4, John Larkin wrote:

On 5 Aug 2019 05:32:08 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Wonderful stuff.

It's impressive how hard it is to shield low frequency AC mag fields.

The experiments on the closed box of pcb are great!
(pgs 16-17)

Win, is there any reference for the x_eff = ~ sqrt(x*D). This is not at all
obvious to me. It's kinda counter-intuitive that a bigger box shields
B-fields better.

George H.

As far as copper foil resistance goes, I just remember, for 1 oz,


1 square of copper is 0.5 mohms and 70 K/W.


but when you ask for 1 oz you rarely get 1 oz.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Mikko OH2HVJ]

Winfield Hill <winfieldhill@yahoo.com> writes:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Some metric comments; many metric people don't have the gut feeling of
AWGs or mils.

Fig 1x.1: at least a few metric wire sizes would be nice to get some
kind of idea. (Temperatures are at least in °C)

Table 1x.1: mm^2 is used for wires

Some mm -dimensions with mils would be nice, we use currently 0.15 mm
track/space design rules.

--
mikko

 

[boB]

On 5 Aug 2019 05:32:08 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

I don't think I knew about the 1dB per wire gauge rule. That's
great...

Another rule that is handy to know is that adding 3 to the gauge very
closely doubles the copper area. I guess that's where the 3dB comes
in handy.

Also, some terminal blocks will say that you can use it for, say, 4
gauge wire but in fact, that only works for solid wire and usually not
stranded wire because of the extra space used up.

 

[Phil Hobbs]

On 8/5/19 8:32 AM, Winfield Hill wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts things off, by
dealing with wire and connectors. Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Wow, an embarrassment of riches today.

One other thing about Teflon wire is that it's a royal pain to strip
using dikes. Irradiated PVC can be stripped in one motion with a pair
of sharp cutters.

Prepreg isn't copper coated--the plating is on the cores. The cores are
pre-cured, but the prepreg flows during lamination.

It's usually best to ask the board house what width to use for a 50-ohm
line. FR-4 varies fairly widely in dielectric constant, and they know
what brand they're using.

PCB propagation is faster on surface levels than inside, because the
effective refractive index is ~sqrt((1+epsilon)/2) = 1.68 vs
sqrt(epsilon) = 2.1.

I'd really like a couple more sentences on FFC/FPC cables. We use them
all over the place, and they're great. The 1-mm ones are much less
likely than the 0.5s to short out if you put them in a bit crooked. The
jumpers you can buy are all made by taking wire and rolling it out flat,
so they can carry lots of current, but if you get them made from plated
Kapton, they are the undisputed champs at getting wires on and off cold
plates.

Twisted pair helps crosstalk if you're really driving and receiving
differentially, i.e. the odd mode, using Ethernet transformers, for
instance. The even mode couples back and forth very easily.

I didn't know about the big-box effect. Cool!

Connector catalogues are full of things that they don't actually stock
but would be happy to make for you if you order 100k pieces. Always
check for ample distributor stock before designing in any part, but
connectors _especially_.


You're _way_ too kind to the Black Magic folks. HoJo is completely up a
pole on the subject of ground currents, among many other things. He had
a video (since pulled down) on an electrostatic demo purporting to show
ground currents following under the traces, but ten seconds calculation
showed that his impedance levels were, like, six orders of magnitude
away from where inductance would make any difference. The "ground
plane" was made up of metal squares affixed to one side of a piece of
glass, with the traces on the other side. The twists and turns of the
"ground current" were governed entirely by corona discharge from the
corners of the squares in the regions of highest E field. Yet he was
giving this cockamamie magnetic explanation. The SNR of the Black Magic
books is no more than 3 dB IMO.

JL and I had a fun go-round here on that some years back--we were
competing to see if we could sell our copies to _somebody_.

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

 

[Phil Hobbs]

On 8/5/19 2:22 PM, Phil Hobbs wrote:

On 8/5/19 8:32 AM, Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts things off, by
dealing with wire and connectors. Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

<snip>

You're _way_ too kind to the Black Magic folks. HoJo is completely up a
pole on the subject of ground currents, among many other things.  He had
a video (since pulled down) on an electrostatic demo purporting to show
ground currents following under the traces, but ten seconds calculation
showed that his impedance levels were, like, six orders of magnitude
away from where inductance would make any difference.  The "ground
plane" was made up of metal squares affixed to one side of a piece of
glass, with the traces on the other side.  The twists and turns of the
"ground current" were governed entirely by corona discharge from the
corners of the squares in the regions of highest E field.  Yet he was
giving this cockamamie magnetic explanation.  The SNR of the Black Magic
books is no more than 3 dB IMO.

JL and I had a fun go-round here on that some years back--we were
competing to see if we could sell our copies to _somebody_. 

It was 2005!

Thread starts at

<https://groups.google.com/d/msg/sci.electronics.design/ldO6UjUDegw/p4RlsUVlDdgJ>

The now-videoless version of HoJo's page is at
<http://www.sigcon.com/Pubs/news/8_08.htm>.

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

Cheers

Phil Hobbs

 

On Monday, 5 August 2019 21:59:01 UTC+2, Arie de Muynck wrote:

On 2019-08-05 14:32, Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Near the flat-cable cross-talk measurements, maybe add a note that using
a GND-signal-GND pattern is a good method to minimize cross talk.
Impedance of a 0.05" FC is then close to 100 Ohms.

In the connector section add a warning against mixing e.g. tin and gold
plated connectors. Maybe mention fretting?

Regards,
Arie de Muijnck

Mitigating EMC on cables can sometimes be solved just by flipping a bit. The bit that controls the slew rate/drive strength of the microcontroller (if that controller has that function)

 

On Monday, 5 August 2019 21:52:56 UTC+2, klaus.k...@gmail.com wrote:

On Monday, 5 August 2019 16:20:18 UTC+2, Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1


Some comments:

For leaded, you can also use Pin in Paste and laser soldering.

Also instead of wave, you can use selective soldering, which is more controlled than a broad wave

For connectors, fretting corrosion is the real killer.

Use decent amount of gold plating, and use the same plating for both plug and socket. Otherwise it makes no sense to add gold.

Also, too much gold is not better either. Just a waste of money

For fretting, to avoid it all together, use a bleading current so that the connection is always "current" driven at at least mA level. Reduces effects of fretting corrosion dramatically

For connectors, between 2 PCBs, use a floating connection. One PCB locked, the other able to float. That way mating is secure, and thermal expansion cycles does not wear out the connection

For the ac resistances, skin effect, maybe mention dowells equation, mostly used for transformers. Just a couple of layers in a winding can increase the DC resistance 100 fold

Cheers

Klaus

Oh, and derate the connections to 50% current. Power dissipation in connectors kill them. Use high dimension wires to the connector to pull the heat away from the connection point. About connection points, use pins that have more than just one touch point

 

On Monday, 5 August 2019 21:52:56 UTC+2, klaus.k...@gmail.com wrote:

On Monday, 5 August 2019 16:20:18 UTC+2, Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1


Some comments:

For leaded, you can also use Pin in Paste and laser soldering.

Also instead of wave, you can use selective soldering, which is more controlled than a broad wave

For connectors, fretting corrosion is the real killer.

Use decent amount of gold plating, and use the same plating for both plug and socket. Otherwise it makes no sense to add gold.

Also, too much gold is not better either. Just a waste of money

For fretting, to avoid it all together, use a bleading current so that the connection is always "current" driven at at least mA level. Reduces effects of fretting corrosion dramatically

For connectors, between 2 PCBs, use a floating connection. One PCB locked, the other able to float. That way mating is secure, and thermal expansion cycles does not wear out the connection

For the ac resistances, skin effect, maybe mention dowells equation, mostly used for transformers. Just a couple of layers in a winding can increase the DC resistance 100 fold

Cheers

Klaus

Avoid SMD connectors, they rip off the traces of the PCB

For high quality connections, use pressfit, which also removes the leaded wave solder process

For best possible connections use gat tight connections. Press fit, crimping, splicing, wire wrap

 

[Arie de Muynck]

On 2019-08-05 14:32, Winfield Hill wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Near the flat-cable cross-talk measurements, maybe add a note that using
a GND-signal-GND pattern is a good method to minimize cross talk.
Impedance of a 0.05" FC is then close to 100 Ohms.

In the connector section add a warning against mixing e.g. tin and gold
plated connectors. Maybe mention fretting?

Regards,
Arie de Muijnck

 

[John Larkin]

On Mon, 5 Aug 2019 14:45:38 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 8/5/19 2:22 PM, Phil Hobbs wrote:
On 8/5/19 8:32 AM, Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts things off, by
dealing with wire and connectors. Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1



snip
You're _way_ too kind to the Black Magic folks. HoJo is completely up a
pole on the subject of ground currents, among many other things.  He had
a video (since pulled down) on an electrostatic demo purporting to show
ground currents following under the traces, but ten seconds calculation
showed that his impedance levels were, like, six orders of magnitude
away from where inductance would make any difference.  The "ground
plane" was made up of metal squares affixed to one side of a piece of
glass, with the traces on the other side.  The twists and turns of the
"ground current" were governed entirely by corona discharge from the
corners of the squares in the regions of highest E field.  Yet he was
giving this cockamamie magnetic explanation.  The SNR of the Black Magic
books is no more than 3 dB IMO.

JL and I had a fun go-round here on that some years back--we were
competing to see if we could sell our copies to _somebody_. 

It was 2005!

Thread starts at

https://groups.google.com/d/msg/sci.electronics.design/ldO6UjUDegw/p4RlsUVlDdgJ

The now-videoless version of HoJo's page is at
http://www.sigcon.com/Pubs/news/8_08.htm>.

Cheers

Phil Hobbs

All my HoJo books are gone, so I successfully unloaded them somewhere.

Pity; in one copy I highlighted the dumb parts.

I'm about to battle a customer who believes a certain uP maker's
recommendations on bypass caps. There is so much nonsense around
signal integrity.

 

On Monday, 5 August 2019 16:20:18 UTC+2, Winfield Hill wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Some comments:

For leaded, you can also use Pin in Paste and laser soldering.

Also instead of wave, you can use selective soldering, which is more controlled than a broad wave

For connectors, fretting corrosion is the real killer.

Use decent amount of gold plating, and use the same plating for both plug and socket. Otherwise it makes no sense to add gold.

Also, too much gold is not better either. Just a waste of money

For fretting, to avoid it all together, use a bleading current so that the connection is always "current" driven at at least mA level. Reduces effects of fretting corrosion dramatically

For connectors, between 2 PCBs, use a floating connection. One PCB locked, the other able to float. That way mating is secure, and thermal expansion cycles does not wear out the connection

For the ac resistances, skin effect, maybe mention dowells equation, mostly used for transformers. Just a couple of layers in a winding can increase the DC resistance 100 fold

Cheers

Klaus

 

On Monday, 5 August 2019 17:58:53 UTC+1, Mikko OH2HVJ wrote:

Winfield Hill <winfieldhill@yahoo.com> writes:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Some metric comments; many metric people don't have the gut feeling of
AWGs or mils.

Fig 1x.1: at least a few metric wire sizes would be nice to get some
kind of idea. (Temperatures are at least in °C)

Table 1x.1: mm^2 is used for wires

Some mm -dimensions with mils would be nice, we use currently 0.15 mm
track/space design rules.

As a euro-peon I've no clue what AWG sizes are, fwiw


NT

 

[boB]

On 5 Aug 2019 05:32:08 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

Did you notice the one note in this version ?

"Paul, litzendraht, and litz, all need to be lower case."


Also, since you have some handy tools in the chapter, one useful tool
that we use often is the electric enamled wire stripping tool of which
there are a few out there... Might be worth a picture...

https://www.ebay.com/itm/Pro-DF-6-handheld-Magnet-wire-Stripping-Machine-stripper-Cutter-110v-US-STOCK-/333086834927


https://www.aliexpress.com/item/32749284319.html

https://sanshinetechnology.en.made-in-china.com/product/EKTnzLDCuQcp/China-Handset-Enamel-Wire-Stripping-Machine-SS-SM06-Repalce-ABISOFIX-Stripper-.html

 

[John Robertson]

On 2019/08/05 5:32 a.m., Winfield Hill wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

On page 17 where you start talking about connectors you state:

“The most unreliable components in any electronic system will be the
following (worst first): 1. Connectors and cables. 2. Switches. 3.
Potentiometers and trimmers.”

My experience with arcade games and monitor (tube and LED/LCD) repairs
would fit electrolytic capacitors between #2 and #3. Or possibly even as
#2...

Is that not your experience too when repairing defective equipment?

Thanks for proving a draft to read, it is informative and I enjoy your
style of humour, which makes for a more readable manual.

John :-#)#

 

On Monday, 5 August 2019 22:47:20 UTC+2, John Robertson wrote:

On 2019/08/05 5:32 a.m., Winfield Hill wrote:
Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1



On page 17 where you start talking about connectors you state:

“The most unreliable components in any electronic system will be the
following (worst first): 1. Connectors and cables. 2. Switches. 3.
Potentiometers and trimmers.”

My experience with arcade games and monitor (tube and LED/LCD) repairs
would fit electrolytic capacitors between #2 and #3. Or possibly even as
#2...

Is that not your experience too when repairing defective equipment?

Thanks for proving a draft to read, it is informative and I enjoy your
style of humour, which makes for a more readable manual.

John :-#)#

Experience from pump industry, electrolytics are number 1 field failure failure item, when mechanics is omitted

 

[Clive Arthur]

On 05/08/2019 13:32, Winfield Hill wrote:

Here's a DRAFT copy of x-Chapter 1x.1, which starts
things off, by dealing with wire and connectors.
Comments and corrections please.

https://www.dropbox.com/s/kz335xwvl5v8gie/1x.1_Wire-%26-Connectors_DRAFT.pdf?dl=1

The mix of units is amusing, and we older Brits can mostly cope, but
what of the rest of the world?

Cheers
--
Clive

 

On Monday, 5 August 2019 20:52:56 UTC+1, klaus.k...@gmail.com wrote:

Also instead of wave, you can use selective soldering, which is more controlled than a broad wave

Robotic soldering is now available from some of the pcb assembly companies
in the UK and no doubt elsewhere. It is mostly used where a few through-
hole parts are needed on an otherwise surface mount board.
For example Newbury Electronics offer this.

John