View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 2/2
Nancy Golden
User Rank
Re: Reverse Polarity?
Nancy Golden   5/27/2013 1:23:49 PM
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
Brought Back Memories
Nancy Golden   5/27/2013 1:05:20 PM
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!

User Rank
Re: Reverse Polarity?
a.saji   5/27/2013 11:13:55 AM
@tekochip: Is it ? I thought it consumes more power in such scenarios.                            

User Rank
Reverse Polarity?
tekochip   5/27/2013 9:18:41 AM
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
Caterpillar Inc. demonstrated this week at Design and Manufacturing Philadelphia that heavy industry can reap big benefits from 3D printing.
The most efficient and ecologically sound automation system may be "eco obsolete" — an older system sustained with obsolete parts.
Flexible electronics will expand beyond its high-profile role in fitness over the next five years, potentially aiding in the treatment of movement disorders such as Parkinson’s Disease.
Design News contributing writer Fred Eady strolls down the memory lane of the homebrew embedded WiFi designs he then wrote reference books around.
With two new tools from LUXeXceL, you can now create and print custom lens designs optimized for your particular application.
Design News Webinar Series
10/1/2015 11:00 a.m. California / 2:00 p.m. New York
9/10/2015 11:00 a.m. California / 2:00 p.m. New York
8/13/2015 11:00 a.m. California / 2:00 p.m. New York
10/20/2015 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.
Oct 5 - 9, Standards for the Internet of Things (IoT)
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