Connections - surface area, travel of electrons, frequency?

OK, this has been bugging me for thirty yeas… yes thirty years… (BTW, my analyst gave me money back when I brought this one up).

When you have a connection that has large surface area… such as a spade or banana speaker terminal… where/how does the current flow? Over the entire contact area? Over the microscopic path of least resistance? By frequency?

Should we seek to minimize the connection area? Big fat spades don’t matter? World Trade Federation?

Bruce in Philly

Those are similar to questions I have always has and never could understand. I’ll be watching patiently from the sidelines. I don’t think normal humans are supposed to understand these processes.

Electrical resistance decreases with increasing cross sectional area. See my post in the Belden Iconoclast thread on how electricity “really” works.

But not linearly with an increase in cross section.

While we are on the subject I have a fairly good grasp of DC. Its similar to water flowing through a hose to my small brain. Amperage is the diameter / area of the hose and voltage is the pressure pushing on the amperage.
The battery goes dead as the stored power drains from it. Got it. The electrons themselves moving along the wire? Kind of grasp although because you cant see them some kind of magic must be involved.

What I can’t understand is AC. Every time someone tries to explain the voltage going back and forth to the power generating station at 60 times a second my eyes just glaze over and brain gets numb. Some electrons must go down one side of the wire and back on the other side? Also you have a separate “neutral” wire and a “ground” wire. Then they both get hooked together in the distribution panel. Really? :thinking:

I continue to maintain that while we (scientists) understand electricity, it remains magic.

Being a mechanical engineer I can understand all of the physical stuff. Tensile strength, yield strength, elongation, brinell hardness, section modulus, moments of inertia, chemical properties of alloys vs end results, machining practices, chip formation, etc., fabrication techniques, fasteners, weld properties, etc. blah, blah, blah. That stuff I get. Its physical so it exists.

But when it comes to electricity I’m like Homer - No way man!

BTW, the contact area on banana plugs is a just very narrow ring around the middle of the plug, compared to large spades.

I am thinking you would want at least the same amount of surface area contact as the surface area of the wire but I don’t think that is possible except with spades and single conductor wires. It seems like the sound would get held up at the connection. More electrical voodoo at work.