Average drift velocity of electron in conductor

I have a question on the derivation of the average drift velocity in a conductor: drift velocity is the average velocity which a free charge moving in a conductor has due to the influence of an electric field applied to the conductor. In a metal, the free charge will be an electron. As they move through the conductor, electrons will frequently bump into ions. If τ is the mean free time of the electron, i.e. the average time between successive collisions, then between two collisions, the action of an external electric field will make the electro...Read more

Does a conductor actively lose charge during electrical breakdown?

Electrical breakdown occurs when the potential difference between a conductor and the medium surrounding exceeds the breakdown voltage. In such scenario, the electric field at a boundary point is strong enough for an electron at the boundary to ionize atoms in the medium, which releases more electrons, causing a chain reaction. My question is, where does the first electron come from? Is it an electron from the surface of the conductor? Do electrons from the conductor continually ionize atoms in the surrounding medium causing the conductor to lo...Read more

Electric field inside a conductor

I would like to clear things up:How exactly the electric field inside a conductor is zero? Let a really "powerful" electric field be outside of it, how can the "few" charges in a conductor balance the field? From my point of view, it's the conductor surface which stops their movement.I'm obviously missing something fundamental here. Thanks in advance....Read more

Using Chassis as a conductor for DC Power Supply Return

Is it considered a good practice to use the chassis as a return path to a DC Power Supply? I have been given a rack mounted device that switches 480 volt power on/off remotely. The remote feature is handle via a Raspberry Pi which is powered via 120v to 5v power supply (http://www.mini-box.com/OpenUPS). I was surprised to find that the return pin on the 5v power supply is tied directly to the chassis and the GND on the Pi is also tied to ground and they are using the chassis as the conductor for the return path. There is only a positive 5v wire...Read more

conductors - How does electricity pass through a surface (or more generally, conductive material with complex geometries)?

I was reading this article on how the breaking mechanism of a Sawstop works. For those who might not know, Sawstop is a table saw fitted with at least a conductivity sensor that detects changes in current passing through the blade as it comes into contact with something other than wood (the table saw operator's fingers, for instance). This got me thinking about how electricity flows through a circular plate. If we connect wires to the plate (see attached diagram) and assuming the wires form a conductive closed loop, would the current change if ...Read more

conductors - Conductive Adhesives?

I'm helping with a kid's Maker's project. We need to attach some LED's to some coin cell batteries for part of a holiday project.Are there any conductive adhesives we can use for this? Durability is not a factor, since the life of the project will be no longer than the life of the coin cell charge....Read more