@ScottSeidman Kind of a general question. Say I want to design a custom signal transformer for 2xMOPP. What traits define the 2xMOPPness in a transformer?

@NickAlexeev Really don't know! Sorry

@NickAlexeev that sounds like a fairly spot-on question for the 'site.

@ScottSeidman Different angle at the same problem. I'm looking for a signal transformer to cross patient isolation.

The requirements for the isolation are 1.5kV, 1xMOPP for mains voltage, 2xMOPP for working voltage (24V).

I can't find an off-the-shelf medical rated transformer. But I found a telecom signal transformer. I've got the UL test report for it. There are no MOPPs in the documentation, because the intended use is for telecom. The transformer is rated for 3kV. The outside dimensions agree with my clearance and creepage requirements.

How can I deduce if this transformer is good for 2XMOPP, or not?

@NickAlexeev I'm not at my work desk, but I recall issues with just where to place my isolation the last time I did something like this. I didn't have to meet IEC60601, as this was a one-off -- it just needed to pass an inspection. I think I found a rated transformer, though, a few projects back.

The last, time, though, I used USB power, and isolated voltage to voltage converters.

@NickAlexeev Just did a quick digikey search for "medical ac dc converter", and went with "off board". The filter menu then offers me choices of approval agency and standard number, down to 60601 sections!

@NickAlexeev Looks like it really is the 4000v isolation voltage between primary and secondary, and 8mm/5mm creepage clearance.

If you really could use a commercial medical rated transformer, or rather AC/DC converter w/ the transformer built in, Digikey is lousy with them. slpower.com/data/collateral/MINT1180_DS.pdf eg

meanwellusa.com/upload/pdf/RPS-30/RPS-30-spec.pdf is like $15

Maybe the issue is trying to find the transformer, instead of the assembly.

@Scott One thing that I've been disappointment in matlab in the last few years is it seems like there is much less effort into improving old toolboxes and mainly adding new ones. I'm also disappointed because it also seems like they are trying to move everyone to the .mlx format for coding which is much less portable and open than a text file. That RF PCB toolbox looks cool, but I think altium also has a PCB FEM that is less expensive than the matlab pricing.

@VoltageSpike Honestly, for most of what I still need to do, I've moved over to Octave. I got tired of seeing students magically acquire very expensive software packages after I mention them, so I try to only mention free software these days. We have a very generous Matlab educational site license, but I still find myself migrating to Octave.

@VoltageSpike That said, I'm curious about Multisim, and I'm asking a student to try something in it for me.

I've been avoiding Matlab (also Eagle, PSpice, and Altium - all limited.) Octave (and R, but I digress) does everything I've needed it to do. Runs on both Windows and Linux.

It'd be different if I needed it for work, but all my design ambitions are personal-only; thus can't justify the expense. Many probably fall in this category (those whom use these tools at work likely didn't have to buy them, the employer did.)

Hey everyone. My question here got closed because someone thought it was a question about "How to fix a faulty consumer product". If you read my actual question, you'll find that this is not true. I clearly asked about a good alternative for a diode that was unknown to me. However, what I did is give enough background information so that people know where my question comes from.

@ScottSeidman I tried octave years ago, the problem is the toolboxes are inconsistent and lack the 'polish' I need to get things done in a commercial setting (I don't want to be tinkering with code, I need to be producing results). I have not tried multisim for a while, because ltspice does everything I need for circuit analysis (and it's free).

@VoltageSpike Multisim isn't just for circuits. It handles mechanical, hydraulic, heat, ....

and I think it does animations.

@ScottSeidman That is good to know. I do all that in simulink or lt spice (Lt spice can do alot when you use b-sources, but all the signals have to be carried around as a voltage... so as long as you know what the signals are, it works).

I really don't care if the question is re-opened and I've been a moderator long enough to know the drill. But I came as a complete newbie with a specific question that was answered perfectly. Maybe using the bit of wiggle-room you have here is better to be more inclusive to newcomers.

@VoltageSpike Ooops, I mean simscape! mathworks.com/products/simscape.html After a while, all these things sound the same.

@ScottSeidman Thanks for the clarification, I thought that's what you were talking about. I've used that before also, but the solver is lacking when compared to LT spice.