Dual Primary Transformer Symbol for Schematic

Hi, i hope this is quick and easy.

I need to place two dual primary/dual secondary transformers. Signal/BEL DPC series. In the schematic symbol library i see only single and split primaries, not true dual primary (can be placed in series or parallel, 4 pins on mains side).

Does such a thing exist? or do i just search google for “Signal DPC-40-600 KiCAD symbol” or whatever?



Just copy a schematic symbol of a transformer that looks sort of like what you want to a project specific library, then open it in the symbol editor, copy one of the coils, change pin numbers and do some more cleanup.

Once you are familiar with such tasks it’s just a few minutes to do so. Editors for both schematic symbols and footprints are easy to use and have a very similar look and feel to their schematics and PCB counterparts.

Ye, thanks Paul. That is my Plan B. But I’ll still need the layout libraries as well, and i do prefer to have the manufacturer’s own work on dimensions and pin assignment. But that is Plan B!

I find it odd that they don’t exist Digi- Key makes a big deal about having such things and they sell the DPC series

For me it is plan A.
Making new symbols or footprints is a path that I know that leads to a result that is satisfactory for me.

If I go searching the 'web, I’m not sure of any outcome, and still have to spend time in verifying the data even if I find something.
Verifying such info is not always straight forward. If you take for example the often used ATmega328, then pin numbering changes, depending on which package it is in.

Some people like sites like snapeda. I’ve seen a few of their automatically generated schematic symbols, and they were just a rectangular box with pins in the same order as on the IC. Yuch!

If you do end up making or even downloading a symbol / footprint you should think through where to put your new symbols. The Kicad libraries are not modifiable so you need to plan your own.

I have windows 10, my personal Kicad libraries are:


They are under Documents or My Documents so they get backed up when my normal files are backed up.

I strongly recommend you create a simple one lead device and save it to your new library. That way if it doesn’t work the way you thought you’ve not wasted a lot of time on your symbol or footprint

thank you. Both good suggestions. I have both. Just cannot believe there is no standard DP/DS model, I guess.

The first time through will cause some hair pulling. After that it will quite easy. Besides no one uses 120VAC transformers anymore. I tried to find the same dual primary but with a 12volt secondary with no luck. In the old days we had loads of the black signal xformers.

2x115 transformers are still manufactured. Useful for dual US / AUS etc markets.
How much power do you need?
There are also wide voltage input off-line switching supply ICs & modules available if you don’t care about the switching noise.
We do as we are making 500W LF linear amplifier.

snapEDA.com seem to have the sort of symbol/footprint you are looking for.
You can also download appropriate files for kicad…

I use them all the time. Many manufacturers - i have supply relationships with 4 - off the shelf at Digikey too.

As Yogi Berra said “no one goes there anymore, its too crowded” :slight_smile:

Anyway, yes i can make one. No, i don’t do it often and prefer not to. Looks like i will however, but first I’ll let BEL fuse and DK reply.

TY all,


now why, after two tries is this at the bottom rather than threaded as indicated? Grrrrr.

BTW I can beyond belief about noise - I’ll be unseeing 3 of the suckers to completely isolate grounds! And yep, the difference is objective and clear, if small.

There’s a dual primary and dual secondary transformer symbol named “TRANSF6” in the standard library. It has no phasing dots, hidden pin numbers, weird name and the core drawn as a solid rectangle, so I guess it’s an older drawing by a different author than the current “Transformer_*” symbols. It might still be of use, though.

You’ll have to draw the footprint yourself, as the library contains mostly “European” transformers (metric pin spacing).

Thanks Radix, i’ll look at that at least as a basis for modificaiton.

Hi All -

I created footprints for the 24VA and 10VA versions of the BEL/Signal DPC series. very simple, just physical outline, pads, numbers, labels. How do i contribute those back to the project for others to use?

Ping! Any help on how to submit to the library?


Search is your friend. There are official docs on the KiCad website and multiple topics covering the details of the process on this forum. I’d recommend searching and reading this forum so you know what to expect, if you choose to contribute.

Here are the official guidelines (if you have a hard time finding them (but I could find them in less than 4 days it took you to ask a second time)): https://www.kicad.org/libraries/contribute/

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.