o_0
I guess I won't be needing this anymore. *throws out a book on Science 101*
Well at least light has a speed. It makes sense that electricity or the "molasses" inside of wires does too.
I might have to go back to this:
Attachments
Last edited:
Why, what this experiment is showing is the drift velocity of electrons (0.1mm/S or slower) which is very slow compared to the speed the E/M wave, the speed of this determined by the dielectric surrounding the wire, or the PCB material (FR4) in the case of a signal on a PCB. So in a vacuum or air it is the speed of light, where Er=1, on a PCB about half this. Cable construction also plays especially with co-ax. Vf=1/Sqrt Er for a lossy line, Vf=1/c * Sqrt LC.
A perfect example of practical uses of these equations are the squiggly routes on PC motherboards. where length matching has to be employed to make sure the signals arrive at the same time to a device (or from) usually found on the DDR memory interface.
I stand corrected. This will give me the determination to complete my 4x TDA1543 PCB design with correctly positioned BCK/WS/DATA lines with proper shielding between each other.
Would it be beneficial to be using thicker traces? I've always thought it to be so but could never find enough evidence online to confirm that it is a benefit to have thicker traces.
I did read a TDA1311A datasheet which states that putting a thick trace underneath the IC to act as a form of couple to reduce noise to be right on the money with my previous understanding. And I will be using it.
Last edited:
It's very interesting that there's an experiment available to actually see the speed visually.
As a dark wave in a crystal no less.
Rather Harry Potter-like.
Generally for digital signals you are looking for an impedance figure of about 50ohms single ended, but don't get to hung up on this figure unless you are doing something like DDR memeory interface. For the chip you reference 0.25mm (0.010") to 0.3mm (0.012") will be a good choice, especially if you are etching at home. The trace width will alter the characteristic impedance of the trace, but this only becomes a concern on higher speed interfaces, for general digital PCBs the trace width is chosen to fit in with the technology and amount of room available for routes on a design. Trace widths from 0.1mm to 0.3mm are used depending on components used and available space. With reference to the GND guard tracks shown between the various digital signals (TDA1311A Datasheet page 11, layout example) these need via's at each end connecting them down to the GND plane (things have changed since 1995) this is to stop them becoming antenna structures (EMC prevention) and improve their shielding ability. Any trace or copper shape that is only connected at one end becomes a dipole structure so can pick up or transmit noise.
A good link:
http://www.x2y.com/filters/TechDay0...log_Designs_Demand_GoodPCBLayouts _JohnWu.pdf
700 deg C is a bit hot for me to play with
A good link:
http://www.x2y.com/filters/TechDay0...log_Designs_Demand_GoodPCBLayouts _JohnWu.pdf
700 deg C is a bit hot for me to play with
I'm sorry but either this guy has misinterpreted what his reference was doing or he's flat out making it up. As a chemist, this wave of darkness sounds to me to be more like copper ions migrating through the crystal. This would be a slow process and one that would be observable on our time scale.
"Wave of Darkness"- good name for a band?
In my recent tests I couldn't tell the difference between anything that successfully got the signal from one place to another. That said, I still prefer low capacitance cables with decent dielectric, just on principle. Maybe your hearing is better and it will matter, but probably not.
The greatest RCA plug of all time, especially for vintage, is the Keystone #567, about $1.11 from Mouser if you buy 10. Not gold and doesn't break if you try to adjust the tension. Fits closely spaced RCA jacks. It has an extension on the back so shrink tubing will stay where you put it.
RG-62 cable is common and very low capacitance, or twist up a couple pieces of Teflon stranded hook up wire with your power drill and a cup hook.
There you go, cables that are every bit as good as any other cables, for under $5 each.
The rule for shielding is that no current should flow in shields. You can use 2-conductor shielded mic cable and terminate the shield at one end only, but I've never seen this make any difference.
In my recent tests I couldn't tell the difference between anything that successfully got the signal from one place to another. That said, I still prefer low capacitance cables with decent dielectric, just on principle. Maybe your hearing is better and it will matter, but probably not.
The greatest RCA plug of all time, especially for vintage, is the Keystone #567, about $1.11 from Mouser if you buy 10. Not gold and doesn't break if you try to adjust the tension. Fits closely spaced RCA jacks. It has an extension on the back so shrink tubing will stay where you put it.
RG-62 cable is common and very low capacitance, or twist up a couple pieces of Teflon stranded hook up wire with your power drill and a cup hook.
There you go, cables that are every bit as good as any other cables, for under $5 each.
The rule for shielding is that no current should flow in shields. You can use 2-conductor shielded mic cable and terminate the shield at one end only, but I've never seen this make any difference.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.