Core material for a low-power flyback

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me high permeability. So they will not be good for high frequency operation , since the BH loss loop will be dominant. Utilize the high u, and go for l ow frequency operation

nd a bunch for you probably takes less effort, but John Larkin likes to cla im that he does electronic design, so he invokes the difficulty of finding a coil winding shop as his excuse.

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ors, and tries to discourage other people from doing it.

inductors by designing them to do the job you need them to do.

passive components - have a lot more variables to play with, and you chance of picking up a commercially available part that will do your job well are a whole lot poorer than they are with things like resistors and capacitors and single winding inductors.

f view is that pushing a personal prejudice that discourages people from ex ploiting an accessible range of design options is decidedly anti-social, to the point of being downright irresponsible.

Who else's opinion would it be?

Of course it does. That doesn't make it the wrong thing to do.

Simple coil winding machines with built-in turns counters seem to be pretty cheap. I thought about buying one in 2010, but we'd just moved into a two- bedroom flat, and were in the process of moving ourselves back to Australia into another two-bedroom flat, and more clutter wasn't what we needed at t he time.

Characterising the transformer once you have wound it isn't a big deal. You 'd have to do with a commercial off-the-shelf device too - manufacturers ar e usually building mainly for one high volume customer, and if that custome r's needs change, the transformers can too.

The irresponsibility is in downplaying the advantages you can get from purp ose designed transformers when you need them, and playing up the difficulti es of finding a coil winding shop (which wasn't that hard when I had to do it for myself).

Why John Larkin does it puzzles me. He recently claimed that he does design his own transformers and get them made when he needs them, but that's not the impression one gets from his posts. He certainly hasn't gone into detai l on any of his transformer designs, which might suggest he delegates the d etail work.

I design transformers, but not enthusiastically. I'd rather buy. I've designed scores of transformers and inductors and generally don't enjoy it.

One exception is transmission-line transformers, which are seldom stock products. Where is yours commercially available?

This one was fun:

It assembles in a few minutes from stock parts, and plugs into surface-mount connectors on the board.

Sometimes it makes sense to use a couple of stock transformers instead of one custom multi-winding transformer. Clever circuit design can usually allow using stock parts.

ing a

ter.

d about

ly fit

ary.

eme high permeability. So they will not be good for high frequency operatio n, since the BH loss loop will be dominant. Utilize the high u, and go for low frequency operation

ind a bunch for you probably takes less effort, but John Larkin likes to cl aim that he does electronic design, so he invokes the difficulty of finding a coil winding shop as his excuse.

eas,

ut

tors, and tries to discourage other people from doing it.

inductors by designing them to do the job you need them to do.

passive components - have a lot more variables to play with, and you chanc e of picking up a commercially available part that will do your job well ar e a whole lot poorer than they are with things like resistors and capacitor s and single winding inductors.

of view is that pushing a personal prejudice that discourages people from e xploiting an accessible range of design options is decidedly anti-social, t o the point of being downright irresponsible.

More parts is usually more expensive and bulkier. If you've got the space a nd really don't want add to a new component to your inventory, that can be an acceptable solution, but it isn't clever circuit design, just cheap.