Light Intensity of Lamps

Discussion in 'General Electronics Chat' started by therock003, Jul 6, 2011.

  1. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    I just want to ask a basic question about how lamps function, since i don't know much about electricity.

    The amount of light emitted from a lamp is proportional to the amount of electricity it receives? So when you want a light source to get dimmed, it's just a matter of cutting down the power it receives? It's just a concern i have about this circular switched the control the lights, and specifically how i can dim the light when i go to bed with no such mechanism so it is not so bright.

    Please excuse my ignorance, and i would really appreciate any information concerning the matter. Thank You.
     
  2. Joshua Gobin

    New Member

    Mar 16, 2011
    3
    0
    Well basically yes ur assumptions are correct ... the cicular device that u see on the dimmer is connected to a variable resistor(resistor is a device that limits or oppose the flow of an electric current) which as is changes its resistance as u turn that knob and as a result increase or decrease the amount of current the lamp recieves... and yes there are electronic devices that can repalce that dimmer..such as a touch , clap or a button dimmer.. any further clarity needed jus ask..
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    Typical modern AC dimmers use triacs to essentially change the duty cycle of the AC voltage.. A variable resistor is a very poor way to do dimming as it will dissipate quite a bit of heat.
     
  4. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    Thanx for the response.

    I also asked around, and i was told that dimmers, only work for specific kind of light bulbs. Not all lamps support dimming.

    Also another thing. How can you set a hot lamp? The small one that is on the end of the hotel bed wall? I would like to be able to dim it so that the person next to me is not irritated by the brightness of the light.
     
  5. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    I don't think the hotel owners will aprove of your plan, nor will the police when they find that you were the cause of the hotel fire!
     
  6. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    As i said i dont know much about electricity, but i seriously doubt that a simple matter of dimming the light, could result on bringing the whole building down!!
     
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    How about you just call housekeeping and request a dimmer bulb?

    Well I do know much about 'lectricity and I strongly suggest you do not attempt to modify the equipment at a hotel as there is a real and serious chance you will start a fire, and if I was on the jury judging you I would have no problem finding you guilty of at least depraved indifference if not actual manslaughter.

    DON'T DO THIS AT HOME, AND ESPECIALLY ON THE ROAD.

    We're what you call professionals, we do this stuff for a living.
     
  8. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    Ok guys relax, i'm just gathering information. I never said i'll try anything that briefly came through my head. I'm not that reckless. If you say that this is no easy task then so be it.
     
  9. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
    395
    For a safe dimmer project, use a dusk to dawn light control thet screws into a socket & bulb screwes into dimmer, but use your own artificial sun via low V , dimmable low power LED.
     
  11. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Might it not be simpler just to use a battery powered LED lamp? You don't want much light anyway, and these days white LEDs are quite efficient.

    Doing this would save you from having to fiddle with the hotel's mains. Apart from the safety angle, if you travel widely you could well find bed lamps with different plug or cap fittings, or even different voltages. You might also come up against small CFL lamps which are non-dimmable.
     
  12. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    A portable solution should come in handy indeed. Do you have some kind of link for the specific product you're talking about? Thank You.
     
  13. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Here is an example to show the sort of thing I mean, but note that I don't particularly recommend it. http://www.betterware.co.uk/productdetails.aspx?pid=059866&language=en-GB This is advertised for sale in UK, obviously if you live elsewhere you may want to buy locally.

    This one uses 3*AA cells: much smaller types using coin or button cells are also made, but their battery life may be too short.

    A battery lamp is also the sort of thing which might be reasonable to make up yourself, or perhaps hack. The simpler commercial ones just connect a three cell battery to the LEDs either directly (not good design) or via resistors (better). You might well find the result still too bright for you, so fitting higher value resistors could help.

    Some bright spark may point out that running white LEDs other than at the ideal current produces poor results, so that dimming requires PWM control. I would not be too worried about that provided that you only want this thing for reading or finding your way to the toilet, not colour photography.

    Some more sophisticated lights use ICs to regulate the LEDs, perhaps with PWM, and if you get one of those hacking for a dimmer result may not be so simple.
     
  14. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
    395
    We frequently used 3 AA's, white LED, switchable 68 Ω, on-off SW,& small RS box as a night light in motor home. Last changed batteries 2003 & 2005, still can reat time with it , but sold motor home last year.
     
Loading...