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Author Topic: What causes light bulbs to flicker?  (Read 4083 times)

Offline The Scientist

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What causes light bulbs to flicker?
« on: 03/01/2011 02:34:50 »
Is it because of the lifespan of a bulb getting 'older' or ? What do you think? Thanks!


 

Offline JP

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What causes light bulbs to flicker?
« Reply #1 on: 03/01/2011 02:39:59 »
Is it an incandescent bulb or fluorescent?
 

Offline The Scientist

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What causes light bulbs to flicker?
« Reply #2 on: 03/01/2011 02:42:48 »
Is it an incandescent bulb or fluorescent?

Mine is a fluorescent bulb. What are the differences between an incandescent or fluorescent bulb?
 

Offline JP

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What causes light bulbs to flicker?
« Reply #3 on: 03/01/2011 04:00:57 »
Incandescent uses a thin metal filament.  When you pass enough of electrical current through the filament, it gets hot and glows.  These kinds of lights dim when less current flows through them, so if you had an uneven current, they would flicker.  When these kinds of bulbs die, they just turn off completely, since the filament breaks and no current can pass through them.

Fluorescent bulbs work by passing a current through ionized gas.  In order to ionize the gas at startup and to keep the current flow regulated, these bulbs have some extra electronics in them.  There are different ways these bulbs can die, but the one that causes flickering is usually that some of the electronics start to wear out.
« Last Edit: 03/01/2011 04:09:23 by JP »
 

Offline Geezer

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What causes light bulbs to flicker?
« Reply #4 on: 03/01/2011 04:15:33 »
Fluorescent bulbs work by passing a current through ionized gas.  In order to ionize the gas at startup and to keep the current flow regulated, these bulbs have some extra electronics in them.  There are different ways these bulbs can die, but the one that causes flickering is usually that some of the electronics start to wear out.

They might also flicker if your supply voltage, or the ambient temperature, is rather low.
 

Offline JP

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What causes light bulbs to flicker?
« Reply #5 on: 03/01/2011 04:52:30 »
Good point.  My knowledge of the engineering and operation of Fluorescent lights is pretty limited.  I looked them up a while ago when I saw a CF bulb burn out in a puff of smoke which melted a hole in the plastic casing around the ballast (the ballast is the bit that regulates the current flow through the gas within the bulb).  That raises a question for me: why are they designed to burn out this way?  Is it because letting a ballast die in less predictable ways could lead to unregulated current and a fire hazard, so that having the ballast self-destruct is far safer?
 

Offline Geezer

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What causes light bulbs to flicker?
« Reply #6 on: 03/01/2011 05:04:38 »
Good point.  My knowledge of the engineering and operation of Fluorescent lights is pretty limited.  I looked them up a while ago when I saw a CF bulb burn out in a puff of smoke which melted a hole in the plastic casing around the ballast (the ballast is the bit that regulates the current flow through the gas within the bulb).  That raises a question for me: why are they designed to burn out this way?  Is it because letting a ballast die in less predictable ways could lead to unregulated current and a fire hazard, so that having the ballast self-destruct is far safer?

That doesn't sound right. They better not be designed to burn out that way. You should take that up with the manufacturer in the most strenuous terms.
 

Offline syhprum

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What causes light bulbs to flicker?
« Reply #7 on: 03/01/2011 19:00:23 »
Filament type lamps when they reach the end of their life will often suffer a break in the filament but keep running as the current is maintained by an arc between the broken ends.
They will often run for quite a time in this condition emitting copious amounts of radio interference they are also sensitive to vibration.
Of course when switched of they will not restart.
 

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What causes light bulbs to flicker?
« Reply #7 on: 03/01/2011 19:00:23 »

 

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