FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Electronix » Misc
Do failing LEDs flicker?
Post new topic   Reply to topic Page 2 of 2 [20 Posts] View previous topic :: View next topic
Goto page:  Previous  1, 2
Author Message
Chris Jones
electronics forum Guru Wannabe


Joined: 06 May 2005
Posts: 278

PostPosted: Thu Jul 13, 2006 11:50 pm    Post subject: Re: Do failing LEDs flicker? Reply with quote

JANA wrote:

Quote:
Go to your local electronics store, and ask for an NE-2. If the mains
voltage is 120 VAC, ask for a 120 kohm 1/4 Watt resistor. If the mains is
220 VAC, ask for a 220 kohm 1/4 Watt resistor.

As for the resistor, it is not very critical. For 120 VAC, you can use
anything from about 100 kohm to about 140 kohm. Double this value for 220
VAC operation. If you go higher with the resistor value, the lamp will be
a little dimmer. If you go lower, the lamp will be a little brighter. If
you go too low, its lifespan will be reduced.

You may have to buy these parts in a minimum quantity, unless the dealer
has opened packages of these parts in stock. Most distributors have a
minimum invoicing. You may have to shop around for a small quantity.


Also many 1/4W resistors are not rated for 240VAC use, but you might be able
to put two in series to get sufficient voltage rating if you can't get the
proper rating in a single resistor from your source of components.

Chris
Back to top
James Sweet
electronics forum Guru


Joined: 01 May 2005
Posts: 1386

PostPosted: Sat Jul 15, 2006 2:30 am    Post subject: Re: Do failing LEDs flicker? Reply with quote

Fred Mann wrote:
Quote:
Hello,
I have a piece of audio gear which has an illuminated power switch. The LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred




I've seen it, but it's rare. Neon glow lamps often flicker as they get
old though.
Back to top
James Sweet
electronics forum Guru


Joined: 01 May 2005
Posts: 1386

PostPosted: Sat Jul 15, 2006 2:32 am    Post subject: Re: Do failing LEDs flicker? Reply with quote

Quote:

Also many 1/4W resistors are not rated for 240VAC use, but you might be able
to put two in series to get sufficient voltage rating if you can't get the
proper rating in a single resistor from your source of components.

Chris



In a pinch, buy one of those little round neon nightlights and take it
apart.
Back to top
RST Engineering (jw)
electronics forum Guru


Joined: 24 Mar 2005
Posts: 313

PostPosted: Sat Jul 15, 2006 3:34 pm    Post subject: Re: Do failing LEDs flicker? Reply with quote

And the source for this little bit of misinformation would be?????

Jim



Quote:
Also many 1/4W resistors are not rated for 240VAC use

Chris
Back to top
Chris Jones
electronics forum Guru Wannabe


Joined: 06 May 2005
Posts: 278

PostPosted: Sun Jul 16, 2006 9:54 pm    Post subject: Re: Do failing LEDs flicker? Reply with quote

RST Engineering (jw) wrote:

Quote:
And the source for this little bit of misinformation would be?????

Jim



Also many 1/4W resistors are not rated for 240VAC use

Chris

Which piece of (mis)information?

Here is an example of a 1/4W resistor not rated to 240VAC usage. I didn't
have to look at many types of resistor to find it, it was the first
datasheet I looked at.

http://www.vishay.com/docs/20135/lcask.pdf

There are plenty of resistors rated at 200 Volts. That is not enough for
use at 240VAC (340V peak). You don't have to believe me if you don't want
to, however the approvals bodies may disagree with you.

Chris
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 2 of 2 [20 Posts] Goto page:  Previous  1, 2
View previous topic :: View next topic
The time now is Thu Aug 24, 2017 10:21 am | All times are GMT
Forum index » Electronix » Misc
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Connecting LEDs to molex nuiseng191 Basics 1 Sun Jul 22, 2007 4:46 pm
No new posts mitsubishi ck3526r picture flicker riverunner Repair 0 Wed Jan 03, 2007 1:48 am
No new posts Getting white flicker spot on Sony TRV460 camcorder D8 ta... Gene Repair 0 Sat Jul 01, 2006 6:37 pm
No new posts Reasons for devices failing throughout the house mungolurky@yahoo.co.uk Repair 19 Thu Jun 29, 2006 11:01 am
No new posts mCd of LEds - which strenght used here.... roxlu Basics 2 Wed Jun 28, 2006 5:05 pm

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums |  Medicine forum |  Science forum  |  Send and track newsletters


Powered by phpBB © 2001, 2005 phpBB Group