Hi Everybody,
I have a Mouser Electronics catalog and was looking for a LED that lights both green and red and will be used for indicating the position of a turnout that is out of sight. Well, Mouser’s has several pages of LED’s to choose from. What exactly would I look for that would serve my purpose and not create a guessing game of what to order. I’m using a 12 volt dc power supply from radio shack to power accessories. Any suggestions?
Thanks,
Ted
They make an 5mm red/green LED,radio shack has them,they look like an regular LED but have three wires on them.
JIM
You want a red/green Bi-Polar LED. The come in 3 lead versions (one common and two control leads, switching power between leads changes the color) and 2 lead versions (switching the polarity changes the color).
Nick
Oregon Rail Supply at http://www.oregonrail.com/items.html has a package of “Dwarf Signals” that come with the LEDs and small plastic housings for them, which are designed as on-layout indicators. These are 3-lead bi-color LEDs. They’re pretty small, maybe 2 mm at most.
I think 5 mm is too big, but maybe not for a control panel.
Because I am in Canada I can’t afford to use Mouser (They ship with UPS and I can pay upwards of $40 just for customs brokerage charges!) So I use Digigkey who are in Minnesota and have a Canadaian distributiotn centre so I dont have to pay those outlandish charges!
I use a Panasonic 3mm diamter (T1 size) Red and Orange LED becuase I have them in stock for other things. The DigiKey part number of P509-ND. The DigiKey site is at: http://www.digikey.com
On this catalog page you will find details of a small variety of two-color LEDs.
http://dkc3.digikey.com/PDF/T053/1680.pdf
I operate these parts at 20mA, for a 12V supply I would use a series resistor of not less than 470 ohms, probably 560 ohm or 680 ohm. The higher value of resistor will give you less light output.
Hope that helps.
JDTORONTO, you might want to check out Active Electronics in Mississauga. I get most of my electronics stuff from their outlet here in Winnipeg–no mail order, no shipping, no hassles. Isn’t it criminal what UPS does to us to ship stuff across the border? I won’t order from a U.S. supplier unless he will ship it parcel post.
They will product Yellow also if you input AC at a certain frequency or switched DC continuously.