I had a PM inquiry on this and not sure I answered correctly, thus this post. The person asked how dual bi-color LEDs should be wired using DPDT and Tortoise. On my control panel I just use one bi-color, using green to indicate straight and red to indicate diverging route position. As I understand it, the person wants to use a bi-color LED on both straight and diverging routes. I'm assuming his question was not answered recently on the Forum, otherwise this is unneeded.
I found this 2013 thread as a reference. Note that the diagram by Renegade1c is a schematic for two basic (parallel) LEDs; e.g., a red and a green to indicate the active route. I suggested that this arrangement could be used by substituting two bi-color LEDs, parallel and in reverse direction to each other. Is that correct? Would the current work out correctly when split between two active LEDs; i.e., enough to light both? Sorry, but I can't get the thread link to insert properly, trying the simple paste as well as the url ... /url trick.
Using a Tortoise to Power LEDs Without Resistors - Model Railroader Magazine - Model Railroading, Model Trains, Reviews, Track Plans, and Forums
I hope this is a worthwhile question. I want to ensure I did not provide an inacccurate suggestion.
BTW, this arose when I checked my Messages, which I almost never do. The inquiry was a month old. Did there not used to be a notification flag at the Messages spot on the right when a new message was received? Is this something that broke and might get fixed?
Paul
Modeling HO with a transition era UP bent
peahrensThe person asked how dual bi-color LEDs should be wired using DPDT and Tortoise. On my control panel I just use one bi-color, using green to indicate straight and red to indicate diverging route position. As I understand it, the person wants to use a bi-color LED on both straight and diverging routes.
it's not clear what is meant by "use a bi-color LED on both straight and diverging routes".
the following diagram illustrates how LEDs can be wired in series with a tortoise machine which i assume is what you did. since the Tortoise is controlled by the polarity of the voltage, current will flow thru only one of the diodes. if not obvious, a 2nd pair can be put in series to indicate the position at 2 differnet locations on the layout. the voltage to the Tortoise may be small and it may move slightly slower
greg - Philadelphia & Reading / Reading
gregcit's not clear what is meant by "use a bi-color LED on both straight and diverging routes".
Greg, here is the inquiry:
" I want to wire up a tortoise switch machine to a dpdt switch along with 2 bicolor LEDs (green/red) that indicate direction for the turnout on both straight and curved routes. I'm having some trouble getting the wiring right, especially for how to wire up the LEDs from the dpdt switch? Do I need to use resistors to avoid overload the LEDs?"
I interpret that as the person wants to put a bi-color LED in his control panel on each leg exiting the turnout; i.e., in the straight route as well as the diverging route. If so, can he just substitute bi-color LEDs in your diagram?
peahrens I suggested that this arrangement could be used by substituting two bi-color LEDs, parallel and in reverse direction to each other. Is that correct?
Yes. I do this all the time.
In fact I have two or three places where I have two operating switches (DPDT) at different locations controlling the same Tortoise. That's four bi-color LEDs in series on either the #1 wire or #8 wire.
I seem to recall when I was wiring them that if I connected the LEDs "anode-to-anode (long lead to long lead) they would give me the red/green I was looking for. Some of my indicators are red/yellow.
I haven't made the labels for this panel yet but you get the idea. The third LED toward the right, on the main is for the drawbridge signal.
IMG_0168 by Edmund, on Flickr
My usual turnout controls are setup so if the toggle is down the turnout is in the normal position. If I have dual control (as the one in the photo is) I mount the toggle so the lever moves right-to-left.
Good luck, Ed
I can see from Greg's diagram that two simple LEDs must be wired in parallel, as current will flow only through the one with the polarity that makes it light. The other LED blocks current and does not light.
For two bi-color LEDs, I presume that they can be wired in series (Ed mentions that) since each will allow current and light (one color) with either polarity. So, should two be wired in series or parallel? Does it matter; e.g., light output, etc.?
peahrensSo, should two be wired in series or parallel?
Series.
Good Luck, Ed
Thanks, guys.
Yes, just take Greg's diagram, and add a second bi-color LED in series. SInce the leads tend to not be marked on them, you might have to experiment with which way to hook it up if you want the selected route to show green and the other route to show red. That's how I had mine wired up, flip the toggle for straight through, the straight route LED lit up green, the diverging LED was red. Flip the toggle for diverging, the striang LED turned to red and the diverging LED turned to green.
Using 12 volts, and having 2 LEDs in series results in the Tortoise getting about 8 volts which is fine - it will run a little slower and a lot more quieter.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
peahrens BTW, this arose when I checked my Messages, which I almost never do. The inquiry was a month old. Did there not used to be a notification flag at the Messages spot on the right when a new message was received?
BTW, this arose when I checked my Messages, which I almost never do. The inquiry was a month old. Did there not used to be a notification flag at the Messages spot on the right when a new message was received?
peahrens Is this something that broke and might get fixed?
Is this something that broke and might get fixed?
Rich
Alton Junction