The Signaling Solution, Inc.
PO Box 25
West Terre Haute,
IN 47885
Phone:(812) 533-1345
Fax:(708) 570-6140

Opto Isolators

    An opto isolator board, in a single package, has a photo transistor and a LED. When you pass current through the LED, it lights and the photo transistor responds to that light and it turns ON and OUT. The transistor can be in on electrical circuit and LED in a different electrical circuit and they are completely isolated form one another. It is a small board that has 8 optical isolation channels on one board.

Opto Isolator
Quite often in wiring model railroads, we have situations where we need electrical isolation in different types of circuitry. For example, In a DCC controlled layout, you may have multiple runs, what is called, a booster district. Usually, these different districts are electrically isolated from each other. In cases like that, when you are using our block detectors like BD8 or BD16, along with our Master Signal Controller, MSC; you have to maintain electrical isolation when you connect a block detector in one district to an MSC, that is also connected to a block detector, in a different power district. So the way, we do this is, we have an opto isolator board.

    One of the Signaling Solution products that we offer is an opto isolator board. In fact, this is a small board that has 8 optical isolation channels on one board. So, if you are looking at the board, the top row of connections is the output pins and the bottom row is the input pins. Your inputs would be in one circuit and your outputs would be in another circuit. Both the sides are labeled. For example, On the input side of channel 1, we have P1 and N1 and on the output side of channel 1, we have a P1 and N1.

    So, now you would hook the P1 and N1 to an occupied output on a BD8 board. So, on the block that’s occupied, it turns ON the LED on the isolator and at the same time, is totally electrically isolated from it, the P1 and N1 connections on the output transistor for that channel would turn ON and they would be connected to the inputs of MSC. So, now we have BD8s in different power districts sending information to MSCs, which are electrically isolated from any of the power districts.We can also use the opto isolator to isolate the BD8 outputs from computer inputs; say, where we want to keep the computer internal circuitry electrically isolated from the model railroad.

 The photograph shows the opto-isolator and its mounting hardware. It mounts very simply with a couple of self tapping screws. There is a pair of nylon insulations to hold it up on the mounting surface, so you can mount it to a piece of wood without any problem at all. You will normally attach to these terminals a 24-26 gauge wire.

    Remember, you are dealing with very low current circuits. So you don’t need lot of copper to do 5that. The mounting holes are drilled such that you can get 24/26/28 gauge wire in there very easily. You will simply strip and insert the wire at correct places and solder them using a 10 to no more than 20 watts small tip soldering iron. This is how you make the connections.

The Signaling Solution, Inc. PO Box 25, West Terre Haute, IN 47885