Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Short Circuit

Short Circuit

Short Circuit

What is the proper definition of a "short circuit"?

RE: Short Circuit

In a closed circuit the impedence become zero at a given point.

RE: Short Circuit

I would add some more ideas to Surge's definition.

Most of the time, short circuit happen when the signal line or the power line (in an electrical/ electronics ckt) come into contact with the ground or return line. This, as indicated by Surge, give rise to a zero impedence resulting in heavy current demand.

Also, there are possibilities that two signal lines come into contact. This also is termed as a short circuit. (Suppose there is an input trigger signal coming into a delay circuit. After a fixed delay, the signal is transferred to a signal processor. If the input to the delay ckt comes in contact with its output, the delay module has no effect. We say, the delay module is short-circuited.)

It's not that a short circuit is always undesirable. Circuit trouble shooters, at times, find the cause of malfunctioning by bypassing(short-circuiting) intermediate stages; power supply units trigger forced short circuit of supply lines (and thereby causing the fuse to blow off) when abnormalities are detected in the circuit while functioning.

Narayanan UM

RE: Short Circuit

Reference: IEEE Standard 100 "IEEE Dictionary of Electrical and Electronics Terms"
The above reference lists several definitions depending on a context, which you might look into.
One of them reads: An abnormal connection of relatively low resistance, whether made accidentally or intentionally, between two points of different potential in a circuit.

RE: Short Circuit

Another aspect of short circuits is that they are not really zero ohms because the involved metals are not superconductors. That can be useful when troubleshooting circuit boards where copper foil runs can be very long, even running to the full physical span of the board.

Once you've discovered that two traces are shorted, you may be able track that short to its location using a digital ohmmeter which can resolve milliohms. You measure the milliohms impedance between the two foils and gradually change the meter probes' points of contact on those foils until you find the minimum milliohms value. When you have done that, your probes will be physically as close to the actual point of the short circuit as they can get and you can do a visual inspection in that immediate area to finally find the fault itself.

It may take some patience to do this, but I've seen many circuit boards rescued from having to be scrapped.

John Dunn
Ambertec, Inc.

RE: Short Circuit

When two conductive parts at different potentials touch, then you have a short circuit.
Once they touch, they are forced to the same potential (at that point), and to compensate for this new forced potential, a new current (aka short circuit current) will develop.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close