HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comments
View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 2/2
Nancy Golden
User Rank
Platinum
Re: Reverse Polarity?
Nancy Golden   5/27/2013 1:23:49 PM
NO RATINGS
Me too, tekochip - if the LED is forward biased, I haven't seen one go out as long as the LED is rated for the current level they are running at. Current limiting resistors usually prevent such issues. A friend of mine said he has seen LEDs put right across the secondary of a 16 volt transformer with a series resistor but no diode to block the reverse voltage - the company told the manufacturer that we don't recommend that and they said they have been doing it for years with no problems. Hard to believe!

Nancy Golden
User Rank
Platinum
Brought Back Memories
Nancy Golden   5/27/2013 1:05:20 PM
NO RATINGS
Interesting article and nice fix. I enjoyed this article specifically because it brought back great memories. As a student, I had my own home-lab set up in my bedroom (my room- mate at the time had two girls so I needed to have it out of reach of curious fingers) and I had the same setup. I was fortunate enough to buy one of the Tektronix scopes that had been used in the labs at school when they remodeled one of the labs and did some upgrades that made a few become available at a price a poor student could afford. Being a faculty assistant at the time allowed me to call dibs on one of them. It was only 20MHz but I was so proud of it and it was my workhorse. When I entered industry the o'scopes that were available (digital storage scopes - wow!) blew me away. My function generator was bought at the sidewalk sale in Dallas - it was a prebuilt trainer that was easy to work on - just pull the top off when something quit working - pretty easy to troubleshoot. It also had AC and DC  power supplies. Love those home labs - they are so much fun!

a.saji
User Rank
Silver
Re: Reverse Polarity?
a.saji   5/27/2013 11:13:55 AM
NO RATINGS
@tekochip: Is it ? I thought it consumes more power in such scenarios.                            

tekochip
User Rank
Platinum
Reverse Polarity?
tekochip   5/27/2013 9:18:41 AM
NO RATINGS
The only other time I've seen LEDs short is from reverse bias.  It doesn't take much current to take them down, either.

<<  <  Page 2/2


Partner Zone
Latest Analysis
We shared our list, now Design News readers tell us which artificial intelligence movies they watch again and again.
Researchers have been working on a number of alternative chemistries to lithium-ion for next-gen batteries, silicon-air among them. However, while the technology has been viewed as promising and cost-effective, to date researchers haven’t managed to develop a battery of this chemistry with a viable running time -- until now.
Norway-based additive manufacturing company Norsk Titanium is building what it says is the first industrial-scale 3D printing plant in the world for making aerospace-grade metal components. The New York state plant will produce 400 metric tons each year of aerospace-grade, structural titanium parts.
Researchers have simplified the fabrication of the geometric requirements for fluid motion in microrobots for in vivo medical applications.
The National Aeronautics and Space Administration’s recently announced plan to put an electric airplane in the air by 2018 is forward-looking, but hardly unique.
More:Blogs|News
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jul 11 - 15, Embedded System Design Techniques™ - Debugging Real-time Embedded Software – Hands on
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9 | 10


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service