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txlines

Started by Unknown September 28, 2021
Everything that conducts is a lossy transmission line.

A solenoid inductor.

https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1

A series string of surface-mount resistors.

A ground plane or power pour.

A wound-foil capacitor.

A wirewound resistor.

A piece of wire in free air.

A via.

A pcb trace, of course.



-- 

Father Brown's figure remained quite dark and still; 
but in that instant he had lost his head. His head was
always most valuable when he had lost it.



  
On 9/28/2021 12:18 PM, jlarkin@highlandsniptechnology.com wrote:
> Everything that conducts is a lossy transmission line. > > A solenoid inductor. > > https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 > > A series string of surface-mount resistors. > > A ground plane or power pour. > > A wound-foil capacitor. > > A wirewound resistor. > > A piece of wire in free air. > > A via. > > A pcb trace, of course. > > >
What if ur brain is a lossy transmission line
On Tue, 28 Sep 2021 12:22:54 -0400, bitrex <user@example.net> wrote:

>On 9/28/2021 12:18 PM, jlarkin@highlandsniptechnology.com wrote: >> Everything that conducts is a lossy transmission line. >> >> A solenoid inductor. >> >> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >> >> A series string of surface-mount resistors. >> >> A ground plane or power pour. >> >> A wound-foil capacitor. >> >> A wirewound resistor. >> >> A piece of wire in free air. >> >> A via. >> >> A pcb trace, of course. >> >> >> > >What if ur brain is a lossy transmission line
What if you posted something intelligent about electronic design? -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
On 9/28/2021 12:26 PM, jlarkin@highlandsniptechnology.com wrote:
> On Tue, 28 Sep 2021 12:22:54 -0400, bitrex <user@example.net> wrote: > >> On 9/28/2021 12:18 PM, jlarkin@highlandsniptechnology.com wrote: >>> Everything that conducts is a lossy transmission line. >>> >>> A solenoid inductor. >>> >>> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >>> >>> A series string of surface-mount resistors. >>> >>> A ground plane or power pour. >>> >>> A wound-foil capacitor. >>> >>> A wirewound resistor. >>> >>> A piece of wire in free air. >>> >>> A via. >>> >>> A pcb trace, of course. >>> >>> >>> >> >> What if ur brain is a lossy transmission line > > What if you posted something intelligent about electronic design? > >
The brain conducts! I know an elderly person who had ECT for psychosis one time, it was miraculous.
On 28/09/2021 17:18, jlarkin@highlandsniptechnology.com wrote:
> Everything that conducts is a lossy transmission line. > > A solenoid inductor. > > https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 > > A series string of surface-mount resistors. > > A ground plane or power pour. > > A wound-foil capacitor. > > A wirewound resistor. > > A piece of wire in free air. > > A via. > > A pcb trace, of course. > > >
Skin effect doesn't model well as a lossy transmission line. -- Cheers Clive
On Tue, 28 Sep 2021 17:31:25 +0100, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

>On 28/09/2021 17:18, jlarkin@highlandsniptechnology.com wrote: >> Everything that conducts is a lossy transmission line. >> >> A solenoid inductor. >> >> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >> >> A series string of surface-mount resistors. >> >> A ground plane or power pour. >> >> A wound-foil capacitor. >> >> A wirewound resistor. >> >> A piece of wire in free air. >> >> A via. >> >> A pcb trace, of course. >> >> >> >Skin effect doesn't model well as a lossy transmission line.
For a modestly long line, one can measure its actual step response and come up with an LT Spice ltline model that is usefully close. I think there are more sophisticated models that include skin effect. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
On 2021/09/28 9:18 a.m., jlarkin@highlandsniptechnology.com wrote:
> Everything that conducts is a lossy transmission line. > > A solenoid inductor. > > https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >
...
> >
Do you mind showing your test setup to get that trace? You must have a back-emf diode on the coil, but that diminishing slope looks wrong... What exactly are you doing to that poor coil? John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."
On Tue, 28 Sep 2021 11:04:15 -0700, John Robertson <spam@flippers.com>
wrote:

>On 2021/09/28 9:18 a.m., jlarkin@highlandsniptechnology.com wrote: >> Everything that conducts is a lossy transmission line. >> >> A solenoid inductor. >> >> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >> >... >> >> > >Do you mind showing your test setup to get that trace? You must have a >back-emf diode on the coil, but that diminishing slope looks wrong...
The setup is in the picture. The inductor goes between an SMA connector and ground. The scope trace is 50 ohm TDR. Closeup: https://www.dropbox.com/s/6kzbwo87olh8am3/PC_1.jpg?raw=1 Given a voltage step from a 50 ohm source, one would expect an inductor to have a spike of the applied step voltage, and an exponential decay towards ground with time constant L/50. What's cool is the initial flat, with the winding acting like a transmission line roughly 800 ps round-trip. I think. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
On 9/28/2021 3:30 PM, John Larkin wrote:
> On Tue, 28 Sep 2021 11:04:15 -0700, John Robertson <spam@flippers.com> > wrote: > >> On 2021/09/28 9:18 a.m., jlarkin@highlandsniptechnology.com wrote: >>> Everything that conducts is a lossy transmission line. >>> >>> A solenoid inductor. >>> >>> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >>> >> ... >>> >>> >> >> Do you mind showing your test setup to get that trace? You must have a >> back-emf diode on the coil, but that diminishing slope looks wrong... > > > The setup is in the picture. The inductor goes between an SMA > connector and ground. The scope trace is 50 ohm TDR. > > Closeup: > > https://www.dropbox.com/s/6kzbwo87olh8am3/PC_1.jpg?raw=1 > > Given a voltage step from a 50 ohm source, one would expect an > inductor to have a spike of the applied step voltage, and an > exponential decay towards ground with time constant L/50. What's cool > is the initial flat, with the winding acting like a transmission line > roughly 800 ps round-trip. > > I think. >
If I remember correctly at one time before it was known whether fiber optics would be feasible, the telcos were going to use helix microwave wave-guides for "broadband" data transmission
On Tue, 28 Sep 2021 16:32:54 -0400, bitrex <user@example.net> wrote:

>On 9/28/2021 3:30 PM, John Larkin wrote: >> On Tue, 28 Sep 2021 11:04:15 -0700, John Robertson <spam@flippers.com> >> wrote: >> >>> On 2021/09/28 9:18 a.m., jlarkin@highlandsniptechnology.com wrote: >>>> Everything that conducts is a lossy transmission line. >>>> >>>> A solenoid inductor. >>>> >>>> https://www.dropbox.com/s/b5eae1jwsdscw4k/PC_3.jpg?raw=1 >>>> >>> ... >>>> >>>> >>> >>> Do you mind showing your test setup to get that trace? You must have a >>> back-emf diode on the coil, but that diminishing slope looks wrong... >> >> >> The setup is in the picture. The inductor goes between an SMA >> connector and ground. The scope trace is 50 ohm TDR. >> >> Closeup: >> >> https://www.dropbox.com/s/6kzbwo87olh8am3/PC_1.jpg?raw=1 >> >> Given a voltage step from a 50 ohm source, one would expect an >> inductor to have a spike of the applied step voltage, and an >> exponential decay towards ground with time constant L/50. What's cool >> is the initial flat, with the winding acting like a transmission line >> roughly 800 ps round-trip. >> >> I think. >> > >If I remember correctly at one time before it was known whether fiber >optics would be feasible, the telcos were going to use helix microwave >wave-guides for "broadband" data transmission
There were trials done using light, in a pipe guided by thermal gradients. I remember when hills had giant sugar-scoop microwave antennas. Now they have cell towers. If we get gen5 or 6 cellular, all that will be gone. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon