Reading electronic schematics

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I was looking at some schematics about DCC signal to Arduino to use DCC to operate the Arduino. The schematic I have found it very detailed but many of the items listed do not have all the specs so I'm not sure what components to purchase. I know I'm very new at electronics so I wanted to know if anyone can help me better understand the schematic as I don't want to purchase the incorrect parts.
See the red "?" for some samples of what I'm not clear about.

There are other items that don't tell me the max amp for a part. Since I'm new and don't know what I should watch for this could be more then I'm needing to try and do myself.

Any thoughts would be great.

The R1 is a 1K resistor but I don't know what watts.


Active Member
R1 can be a 1/4 watt which are easy to find. If you are asking about the voltage for C1 then 50 volts or better should do it. U2 is simply a full-wave bridge IC with the part number as shown MB110S.
I was thinking of using 1/4 since I have handful of different 1/4 watt resistors.
For the capacitors I wondered if the only information provided (the uF size) is all I need to worry about.
The full-wave bridge I noticed there are different sizes that have some settings like the mA each one is rated. Also, there are some that numbered the same but just Sutton little differences. I just want to be sure I don't get one passing to much current and cause the arduino to get damaged. Just trying to lean / understand about the details I'm ignorant to since I'm not knowledgeable to all this.

Thanks for the help.


Active Member
For a 1uF cap you should be safe with a aluminum or tantalum. There are many different styles (body shape, lead position) but you can probably sort that out yourself based on your needs.
The part number for the bridge should be sufficient to specify the exact part - unless it is an incomplete part number.

Where did you get that schematic? It looks like one I should keep on file.

I worked in the electronics field as a digital circuit designer for many years. I have forgotten a good deal of specific information but I remember the basics.

I assume the small differences I see on the components wouldn't make a big difference but I would like to ask and learn as I just don't know. I feel better about building this myself if I know the whole picture and know I'm not going to blow up my home doing it (LOL). I know that the amount of forward current or such details from a component could make a world of difference. I just like to learn more if I can to feel better about what I'm doing.

The Schematic I got off a web site about building a connection from DCC to the Arduino. I think the site was a in Europe someplace. If you like the original PDF let me know and I can send you a copy. Also then you may see any detail I may miss.



Active Member
Hi Dave,

Yes please email the PDF file. Thank you.

You mention "small differences" - what exactly are you referring to? If you can tell me what the differences are I can tell you if it matters or not.

Hi Frederick,
I will work up an email with examples of the differences I question for youto review. I'll send those along with the PDF file you you. We can discuss more there and follow up here with the findings.

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