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
Texas Instruments has produced an e-book intended to get you up to snuff on the Industrial Internet of Things.
A South African startup is combining recycled plastic with solar power to give underprivileged school children a stylish schoolbag that also supplies them with light to study by.
An in-depth survey of 700 current and future users of 3D printing holds few surprises, but results emphasize some major trends already in progress. Two standouts are the big growth in end-use parts and metal additive manufacturing (AM) most respondents expect.
Technology and global expansion are playing key roles in making manufacturing an attractive field for women to join, more than ever before, said the president of a woman-owned family of companies.
A few years ago, reshoring roared onto the scene as the next great movement in manufacturing, but the data so far reflect otherwise.
More:Blogs|News
Design News Webinar Series
8/13/2015 11:00 a.m. California / 2:00 p.m. New York
6/25/2015 11:00 a.m. California / 2:00 p.m. New York
6/24/2015 11:00 a.m. California / 2:00 p.m. New York
6/11/2015 11:00 a.m. California / 2:00 p.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.
Aug 31 - Sep4, Embedded System Design Techniques™ - Writing Portable and Robust Firmware in C
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7


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