I am always trying to learn more, so here is a cool site that gives a little info about working with LED’s. (I have little electrical knowledge, except for block wiring by Atlas)
The key thing to remember with LEDs is that they operate on CURRENT not voltage. Thus, you ALWAYS need a resistor to limit current to a safe level. LEDs also do not like current applied in the wrong direction - an ordinary diode can stand up to this, but LEDs really can’t. So your power source should be clean DC power. Don’t use an old cheapy train set power pack, for example.
If you downloaded the calculator, then you have a method of figuring out what resistor to use. When figuring the LED current, there’s really no way you can determine what value to use other than the manufacturer’s specifications for that particular LED.
When it comes to building lighting, the generic white LED does a good job of representing fluorescent lighting. They tend to have a slightly blue tint to them. They’re also good for modern diesel headlights. For older nits I prefer the ‘golden white’ LEDs which have a more yellowish color to them when lit and look more like an incandescent light bulb.
I use a lot of LED’s on my layout and layouts from the past…they make great searchlight targets, panel lighting, and for locomotives; using white light leds facing fiber optic strands to the headlights make a wonderful, powerful locomotive headlight…Chuck
Bi-color LEDs are just the ticket for simple panel indications when using Tortoise switch machines. I just wire a pair cathode to anode and put the remaining leads in series with one of the legs of the motor supply. One LED will be green, the other red then insert them into your panel for the appropriate track designation! E-Z
No resistors needed as the switch motor acts as the current limiter!
On my layout all “normal” switch routes are green so I can tell at a glance if any switch is set for “Reverse”
Ed
LED’s and any electrical device operate on current and voltage. The current limiting resistor drops the voltage thus reducing the voltage to the LED. Less voltage to the led means less current and power over a fixed resistance.
Ron K.
I have a friend who did a lot of reasch into LEDs for his RC airplanes. He explains the basics of LEDs and the current limit resistor. He also has a calculator at the bottom of the page to detemine the size of resistor needed. I have his permission to post the address here: