Bachmann Online Forum

Discussion Boards => HO => Topic started by: Grumpy468 on April 05, 2021, 01:02:20 PM

Title: LED lighting
Post by: Grumpy468 on April 05, 2021, 01:02:20 PM
I was given this site by a friend, i am looking at my layout and thinking about placing an order. The LED strips are 3 led lamps in a 2" segment, there are also single bulbs and some flashing ones that go red green. I guess all i can do is buy some and try them, see how bright they will be? What are you guys using for lights on the layout?

I want to buy some actual molded working light fixtures for street lamps and outside wall lamps on buildings. Who has the best selection of those?

https://www.allelectronics.com/item/ls-12-nw/12vdc-led-light-strip-neutral-white/1.html

https://www.allelectronics.com/index.php?page=seek&id%5Bm%5D=pattern&id%5Bq%5D=led-12w

The flashing ones.These require a 550 ohm resister to drop voltage from 12vdc to 2.5 vdc.

https://www.allelectronics.com/item/led-6f/5mm-red-green-flashing-led/1.html
Title: Re: LED lighting
Post by: Grumpy468 on April 05, 2021, 05:16:09 PM
Placed the order for all the led lites. will post pics and details of how they work.
Title: Re: LED lighting
Post by: OlddManWithHO on April 06, 2021, 08:12:50 AM
Grumpy,

     I buy those LED strips by the reel.  Use them in my buildings and I've used them in my passenger cars.  The Passenger cars need a small voltage regulator and a 470UF capacitor to even out the flickering.

Roger
Title: Re: LED lighting
Post by: know2gogg on April 12, 2021, 04:03:55 PM
Hi Grumpy, these days the LEDs are made using different technologies and they come with different luminosity/brightness. I use LED's a lot -  on the locos, in cars, on the layout for special decoration and effects. I prefer to test them before deciding what drop resistor to use.

For example, if its very bright, you may need to put only 5 mA or even 1 mA current through it. If its not bright, 10 mA will work for most cases, or 20 mA for street lights.

First, you need to know the forward voltage drop on your LED. Usually it is posted on the specs when you buy it, or it can be measured by some DMM in diode measuring mode.
Lets, say the LED forward voltage drop is 2 V. And your electrical source is 12 VDC. The way how drop resistor value is calculated: 12 V (source) - 2 V (LED) = 10 volts, this is LED drop voltage.
If you need to put 5 mA through your LED, the resistor value is: 10 V / 5 mA = 2 kOhms.
If you need 10 mA, the resistor should be: 10 V / 10 mA = 1 kOhms.

If you want to connect two LEDs in series, your LED drop will be 12 V - 4 V (2xLED) = 8 Volts.
For 10 mA LED current, the drop resistor value is: 8 V / 10 mA = 820 Ohms.

Enjoy!
Andrew