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
From faux innovations, to fake artificial intelligence, to an Internet-ready Porta-Potty, here's a look at our favorite hoaxes throughout engineering history.
The implementation of a new diesel fuel standard in the US has considerably improved the environmental performance of diesel vehicles. The Environmental Protection Agency (EPA) says that the new ultra-low sulfur diesel (ULSD) fuel has combined with other improved technologies to reduce diesel's particulate matter (PM) emissions by 99%.
A France-based inventor has built drones modeled after i>Star Wars spacecraft. And he's showing everyone else how to do it, too.
Nearly 30 years after its release, 'New Coke' is still a lesson in product failure for engineers.
Transient-voltage-suppression diode technology eliminates surges and enhances vehicle safety.
More:Blogs|News
Design News Webinar Series
3/31/2015 11:00 a.m. California / 2:00 p.m. New York
2/25/2015 11:00 a.m. California / 2:00 p.m. New York
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Mar 30 - Apr3, Getting Hands-On with Cypress’ PSoC
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67


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

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service