Sometimes, when a wobbly charger is plugged in a socket, it takes some iterations to ensure a proper 'contact' between the charger Pin and Socket, for charging to start.

So what exactly is a 'contact' between the two surfaces.

To what extent are the two metal surfaces touching each other? Are the two surfaces touching each other at atomic levels? Are the surface atoms of charger pin enmeshed with the surface atoms of the socket pins? At even more micro level, does the flow of electrons takes place thru a continuous bridge between the socket pins and charger pin or at some point there is actually an induction of energy where power just leaps frog into space and enters the charger pin like it happens in case of a transformer (primary to secondary jump).

Thanks in adv and regards,
Rahul

 

The answers to questions like these are not simple and depend heavily on the level of detail and abstraction you want to operate on.

For instance, before you can answer a question like, "To what extent are the two metal surfaces touching each other?", you need to establish what it means for two surfaces to touch each other, period.

One person might be content to think in terms of materials being a continuous medium, others might want a level of detail consistent with atoms and electrons in a lattice of some kind, while yet others want to talk quantum mechanics and wave functions. Very different discussions.

 

Sometimes, when a wobbly charger is plugged in a socket, it takes some iterations to ensure a proper 'contact' between the charger Pin and Socket, for charging to start.

So what exactly is a 'contact' between the two surfaces.

To what extent are the two metal surfaces touching each other? Are the two surfaces touching each other at atomic levels? Are the surface atoms of charger pin enmeshed with the surface atoms of the socket pins? At even more micro level, does the flow of electrons takes place thru a continuous bridge between the socket pins and charger pin or at some point there is actually an induction of energy where power just leaps frog into space and enters the charger pin like it happens in case of a transformer (primary to secondary jump).

Thanks in adv and regards,
Rahul

I realize this is a slightly older thread but for some reason I am just seeing it now and had some help to offer.

Hello,

Basically we usually just think about this in practical terms because there are a lot of micro variables as WBahn pointed out.

That simply means the contacts have to be clean and that means free from oxidation mostly. Gold plating helps, and contact pressure helps. If the contact pressure is not enough, it may not make any contact or will be detected as a poor contact by the hardware/software.

There is one kind of connector that is somewhat recent that is often called a "magnetic connector". This is a connector that does not relay on a physical holding mechanism to keep the contacts together tightly, but rather on a magnetic attraction between two magnetic surfaces. The magnetic surfaces join when the contact is first made and that holds the connection place, but when that happens the contacts that protrude a little make contact with the contacts in the device and that forms the actual connection.
Apple typically uses this on a lot of their devices but there are stand alone magnetic cables that you can use with your cell phone to charge. That means you never have to use the USB C port more than one time on a new phone. You plug in the insert, and then you never have to unplug it. It saves the C port over a long time period. The magnetic connector on the end of the cable gets stuck to the insert on the phone and that's how you 'plug' the charger in from then on.

The secondary problem here is that if the magnetic surface has some small debris on it, the two magnets will not come into close enough contact for the actual electrical contacts to touch, and that means there will be no electrical connection even though the connectors stay stuck together. The solution is to clean the magnetic surfaces and that usually works. The electrical contacts are usually gold plated.