Smart questions
Smart answers
Smart people
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • 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!

Join Eng-Tips
*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.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

1BrickShort (Aerospace) (OP)
11 Jan 08 17:42
I have a reed switch that has been working properly for multiple cycles, then out of the blue it is showing a short circuit. The reed switch itself has been soldered to a circuit board and embeded in epoxy, so I do not have the luxury of being able to physically touch the switch or board.

Has anyone seen an effect on a reed switch that would cause it to suddenly short for no good reason, then remain shorted indefinetly even though there was no magentic field present?

Is it possible for a voltage spike to cause this? What else could cause this effect?

I am confused by this.

The idea of embeding the switch assembly in this expoxy has been proven through experience on the product line, so I am fairly convinced that the effect is not coming from the efects of the epoxy...

Does anyone have an idea as to what this could be?

1BrickShort
IRstuff (Aerospace)
11 Jan 08 17:54
As with any switch, overcurrent can potentially cause the contacts to weld together

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

1BrickShort (Aerospace) (OP)
14 Jan 08 15:56
Well, the welded reeds was the correct answer. I found a potentiometer this morning that was shorting in the circuit and causing the failure. Through testing I could repeat the effects consistently...the conclusion is that we shouldn't nessisarily buy from the cheapest bidder!!!

Thanks for the input

1BrickShort

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!

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