Model Railroading > Overhead Lighting - Dimmable PAR 30 LEDs

For my overhead layout lighting I am using dimmable track lights.   The bulbs I am using are Satco PAR 30 Floods, 5000K, 14-75W, S8936.   My complaint is the bulbs don't dim very low.   I have used two different dimmers with the same results.  Both dimmers are name brand and are LED compatible.  I am thinking it is just that particular bulb.  In addition, while the 5000K is good for photography, in my opinion it is too "white" .  I am looking for input on what others are using for LED dimmable bulbs and opinions and/or results.   Getting the overhead lighting right is a big part of the model railroading experience.   Any input is appreciated.
Mark
Casselton
Houston, Texas


 

The problem with LEDs in general is they don't 'ramp' very well. I do the whole Christmas light synchronized show thing, and LED's need about 40% to turn on, then you can ramp them or dim/undim them. For color splashing and controllable of colors, LEDs are the key. For 0-100% dimmable lights, incandescent lights are still the only true viable option. 

Mike ONeill
Parker, CO

I tried "dimmable" LEDs in one of my home lighting fixtures and couldn't tell the difference between dim and bright.  I was wondering whether I used the wrong brand or if it was just a characteristic of LED's...sounds like the latter.

OTOH, I've been experimenting with surface mount LEDs for lighting an HO locomotive I'm working on, and have found I'm able to tune their brightness reasonably by putting various regular diodes in series with them.  Maybe I should hurry and patent something.

Casselton Wrote:
-------------------------------------------------------
> For my overhead layout lighting I am using
> dimmable track lights.   The bulbs I am using are
> Satco PAR 30 Floods, 5000K, 14-75W, S8936.   My
> complaint is the bulbs don't dim very low.   I
> have used two different dimmers with the same
> results.  Both dimmers are name brand and are LED
> compatible.  I am thinking it is just that
> particular bulb.  In addition, while the 5000K
> is good for photography, in my opinion it is too
> "white" .  I am looking for input on what others
> are using for LED dimmable bulbs and opinions
> and/or results.   Getting the overhead lighting
> right is a big part of the model railroading
> experience.   Any input is appreciated.
> Mark
> Casselton
> Houston, Texas
>
>
>  

LED lights are digital devices, on or off. They are diodes so on AC they only flow current and light up 50% of the time. Dimming them involves changing the frequency of the AC or changing the sine wave. If you make the off side longer than the on side the light is dimmer than if both sides of the wave are equal. You need to be careful with the frequency so you don't get a flicker.

You must be talking about those used in household service as the strip ones are toaly dimmable as am using them on my layout. Also if your wife has a sewing machine I put them under the arm where normaly there is no light. The ones I got were ordered off of ebay from china
they came with a dimmer in line and about four feet of strip leds that had adhesive on one side. Keep momma happy and you can also railroad happy.

I posted about all I know about lighting leds. They are not like incandescent lighting for models. For those you drop the voltage value or cut in a resiztor or diode to darken the output.

With an led if the voltage drops below 2.4 v the led goes from near normal brightness to off. It is the same powering up.

Beyond the electronics gurus are going to have to jump in and help.