Why do low energy lightbulbs take so long to reach full brightness?

  • 1 Replies

0 Members and 1 Guest are viewing this topic.


Offline thedoc

  • Forum Admin
  • Administrator
  • Sr. Member
  • *****
  • 513
    • View Profile
Oliver Clark  asked the Naked Scientists:
   Hi Chris,

(Great Show)

Why do energy saving lightbulbs take so long to get to a bright light and why is this level still dimmer?

Oliver Clark (Aged 12)

What do you think?
« Last Edit: 01/04/2012 12:50:01 by _system »


Offline Soul Surfer

  • Neilep Level Member
  • ******
  • 3345
  • keep banging the rocks together
    • View Profile
    • ian kimber's web workspace
Presumably you mean the ones based on small fluorescent tubes wrapped up.  There are two reasons for this.  Firstly the tubes depend on mercury vapour to run properly and need to warm up a bit to work properly.  Secondly to avoid excessive stress on the electronic driver circuits.  While the tubes are warming up they tend to need a bit of extra power to get them going.  with non electronic tubes this is easy and they warm up much quicker but with the electronic circuits you would need much more robust bulky and expensive components to allow for this quick warmup and they would be under utilised for the main part of the life of the bulb so it is a balance between reliability and warmup speed and the compact tubes compromise by having a slowish warmup of a minute or two.
Learn, create, test and tell
evolution rules in all things
God says so!


Guest Monique

  • Guest
« Reply #2 on: 27/11/2016 03:47:06 »
Can you tell me what type of bulb I should use that would be dim when I turn it on that eventually gets brighter? I can't stand the shocking brightness when I use any other led bulbs and have nearly gone mad trying to find a bulb that doesn't force me to put on my sunglasses in the bathroom when turning on the light. Would love to hear what your recommendation is. Thank you in advance! Monique