Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Speed Electricity Travels
Name: mike b caciari
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993

How fast does the electrical current travel?

2Author: david r munoz This is an interesting question. I wish that I knew the answer. My first thought is that it travels at near the speed of light but light travels slower within our atmosphere than it does in a vacuum, so I am wondering if the medium through which the electricity\pass passes makes a difference.

Current represents the charge per unit time that flows in a conductor what we would need with the this value is the charge capacity per unit length of the conductor. I am sure that it would depend on the resistivity.

This would be a very good question for the Physics section. Unfortunately, I do not believe that there is an electrical engineer that answers questions on this section of NEWTON and my background is in Mechanical but I am sure that the physicists would be happy to help.

david r munoz

There are two aspects to this question: how fast does an electrical signal travel, or how fast do the current carriers travel? Dr. Dave is correct that the signal travels at the speed of light. This is somewhat slower in a metal wire than it is in vacuum. But the actual charge carriers (electrons if it is a metal) move much slower. This is determined by their interac- tions with the metal atoms. It is measured by a quantity called mobility.


Click here to return to the Engineering Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory