Adding a resistor to a NON LED light


goscrewyourselves

goscrewyourselves

I'm the one
This is my complete wiring novice side coming out...

Will adding a Resistor to a non LED light have the same effect as it would if added to an LED light? In other words, will the intensity of the light be reduced as it should be with an LED light? Personally, I can't see any reason why it couldn't be done, but I could be completely wrong as well :)

Reason I am asking is because I want to add a light to the garage on my small Diorama, but I want the light to be very dim, dimmer than what a standard non LED light (the model power stick on type) would be.
 
One word: "Ohm's Law"

Wait... that's two words... oh well.

I rather not give you the answer. You can work this out for yourself if you study "Ohm's Law" and give it some thought. And that knowledge will serve you well in the years ahead.

But if you really get stuck ask again.
 
Hey Tony,

I have a suggestion, use a potentiometer (dimmer switch) and a 110v c-7 Christmas candle etc., night light, or other fixture. Those bulbs can be found everywhere. You could pick up all you need at a good hardware store. Go to the electrical section and tell them what you are doing and they can help you pick out what you need.

The potentiometer (dimer switch) is variable will allow you to dim the light to your to suit you. The upside of doing this is you can then simply plug it in to any 110v wall outlet.
 
Louis, I like the idea of being able to "dim" the lighting, but wouldn't the lights you are speaking of be a little large for a HO layout building? Perhaps I am not thinking about the same type of light/bulb.

Actually, it would be nice if someone made a dimmer type switch for layout lighting that run of your AC/DC power supply or a bus board.
 
You are right Tony, I took a look at your garage in the other thread again and it may look like a bon fire if you used a c-7 bulb!

Forgive me I am always thinking in O gauge.
 
If you have an electronics store near you that sells parts you can get a potentiometer (dimmer switch) ) that is rated for the output of the power supply you are using. Radio Shack use to carry this stuff and I think you can still order them through radio shack.
 
Thanks Louis, you are an internet search guru :) I do have a Radio Shack near me and have to drop in sometime today to pick up some "heavy duty" resistors, so might pick up a couple of those potentialometer thinga me gig thingies. Please excuse the techo terminology, impressive though, isn't it :cool:
 
Hey Tony, I am no guru, but thank you. It helps to know what you are looking for.

That part is actually a rheostat. Is still just basically a variable resistor. If I am not mistaken Radio shack will ship the item to the store for you for free.
[h=1]25-Ohm 3-Watt Rheostat[/h]Model: [h=2]271-265[/h]Catalog #: 271-265

As the old saying goes "one hand washes the other" When I get around to doing scenery I will be asking you for help.
 
I like the simple approach.
If your voltage is 12v, why not find a 20v bulb, and use that with no resistor, or anything?
 
Bruette said:
Hey Tony, I am no guru, but thank you. It helps to know what you are looking for.

That part is actually a rheostat. Is still just basically a variable resistor. If I am not mistaken Radio shack will ship the item to the store for you for free.
25-Ohm 3-Watt Rheostat

Model: 271-265

Catalog #: 271-265

As the old saying goes "one hand washes the other" When I get around to doing scenery I will be asking you for help.
Click to expand...

Thanks Louis and when you come to do your scenery - I am at your disposal for anything you want to know, so ask away. That being said though, there are plenty of people here that are far better at scenery than I, all I can do is tell you how I do things, and that may not be the best way but works for me :)

bnsf971 said:
I like the simple approach.
If your voltage is 12v, why not find a 20v bulb, and use that with no resistor, or anything?
Click to expand...

I like simple too, especially when it comes to electronics. I work in HO Scale, which is a little more restrictive when it comes to purchasing things of the shelf from non railroad model stores. I thought LEDS would do the job, and they will with the right resistor attached to them, I just have to find the right resistor to obtain the lighting look that I am after.

With my old layout, I used the Model Power stick on incandescent lights which worked pretty well and I was able to adjust the brightness of the lights. I just can't remember how I did it. As such, I like the idea of being able to dim the lights individually, especially for buildings and street lighting. I don't want all the lights to be the same brightness as that would be too unrealistic for me.
 
You could simply use a DC train power pack, which can be found for cheap. Just adjust the throttle and use the track output to power your lights.
 
A 25 ohm rheostat really isn't going to be of much value .... 25 ohms resistance isn't enough to make much of a difference.

First and foremost - what voltage are your bulbs ? (I would assume either 1.5 or 12 volt). Second, what are you using to power them ?

The simplest and most accurate way of doing this would be to get yourself a 2500 or 5000 ohm potentiometer. You want the linear taper variety, not the audio taper. Using your meter (if you don't have one, get one - they are cheap and VERY useful) attach the probes to the middle and one end lug (there are three lugs, doesn't matter which end one). With your meter set to resistance, adjust the potentiometer to read the maximum ohms. Now insert the potentiometer in series between the power supply and the bulb using the same two lugs. The bulb should be off. Now, slowly turn the potentiometer down until the bulb lights (if it doesn't light, your power supply voltage is lower than the bulb's rated voltage). Adjust the potentiometer to the desired level of brightness you want. Now remove the potentiometer from the circuit, and using the meter again, measure the resistance across the same two lugs again. This reading will be the value of resistor you should install with the bulb to give you your desired brightness.

Mark.
 
Thanks guys , appreciate both your thoughts and both make sense.

I was using an AC/DC train power pack but suspect the "throttle" and AC Side are kuput as turning the throttle does nothing!

Mark, I don't have a meter but obviously need one and I like the idea of being able to "read" the strength of resistor I need for a given amount of light. That, being added to a working DC power pack would be perfect I think.

Thanks to both for your in put - it has helped a lot.
 
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