When hooking a risistor to a LED you place it in series. When you hook a resistor to only dim a bulb having the correct voltage do you hook it in series or parallel?
Thank you
If you want to reduce the voltage going to the bulb, which would make it dimmer, then put the resistor in series with the bulb.
For me, the right thing to do is to select a combination of bulb and power supply so that you don't need resistors. I use a 12-volt power supply and almost all of my bulbs are 16-volt. By running the bulbs at a bit less than their rated voltage, they give out a warmer, softer light, and they will also last a lot longer. You may want bright, harsh lighting if you model the modern era, though.
LEDs need resistors to limit the current. Bulbs don't have that problem, but you still have to be carefult not to put too much voltage across either of them.
It takes an iron man to play with a toy iron horse.
MisterBeasley If you want to reduce the voltage going to the bulb, which would make it dimmer, then put the resistor in series with the bulb. LEDs need resistors to limit the current. Bulbs don't have that problem, but you still have to be carefult not to put too much voltage across either of them.
And, of course, if the incoming voltage exceeds the voltage requirement of the bulb, bye bye bulb.
Rich
Alton Junction
I am using a 12 volt supply with a 16v bulb but simply would like my street lights to be a little warmer and not so in your face
Brian
brianmarie I am using a 12 volt supply with a 16v bulb but simply would like my street lights to be a little warmer and not so in your face Brian
So, use a 9volt supply, ro maybe a 6 volt supply. Wall warts are cheaper and safer than power resistors.
An incandescent light bulb is a resistive device : It draws current : Excess voltage will kill it.
An LED is a diode and does not draw current, thus excess current will kill it. It is more akin to a rectifyer than a light bulb, thus you must put the resistor or some other device in the circuit to use the current. An LED will operate at almost any voltage, just so long as the current does not exceed specs and kill it.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Brian:
Why not just get yourself a simple household dimmer switch and wire it in between the 12v source and the lights. You will be able to set the brightness exactly where you want it. I don't think it matters that the dimmers are rated for 120v. That is a maximum. If it won't work for some reason perhaps somebody could explain why not.
EDIT: Read Mark R's post below - my idea won't work.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
A regular household dimmer switch won't work. They are designed to work on a 110 volt AC circuit and create the dimming by stretching the AC sine wave - similar to the zero stretching DCC systems use to run DC engines. Also the same reason some bulbs "sing" when dimmed, just like the motors in DC engines do.
You could use a regular linear potentiometer between the supply and lamp as long as the wattage rating is sufficient.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Get a cheapo power pack and use the variable DC output/throttle instead of a fixed DC/AC output. An incandesent low voltage bulb will work on AC or DC.
If you say you are running 16 volt bulbs at 12 volts and you want them ''warmer'' what do you mean by that? Brighter/dimmer. If you run them at 16 volts, they will be brighter, but also hotter, so being close to say plastic for long periods of time, they would distort and in some cases melt the plastic, along with not lasting long.
Frank
Mark:
Thanks for explaining why my suggestion won't work. I should have kept quiet.
By warmer I mean not as bright and more yellow or wamer in color.
Thanks
brianmarie By warmer I mean not as bright and more yellow or wamer in color. Thanks
Correct. Warmer (in lighting) is a color. The color of light is measured in degrees Kelvin. You can look all of this stuff up. You can always put a dab of glass paint on the lamp if you are trying to emulate a certain color, but the result will be the color of the lamp + the color of the paint.
You get a warmer color by using a LOWER Kelvin temperature. [Go Figure!]