Your picture looks like a transformer but it is not. It's a coupled inductor. https://electronics.stackexchange.c...-between-a-transformer-and-a-coupled-inductor

https://www.ti.com/lit/an/slyt380/slyt380.pdf

Already posted before and talked about in this thread

 

A "coupled inductor" that is not a transformer in any form is commonly referenced as a SATURABLE REACTOR, or MAGNETIC AMPLIFIER. It uses a DC current in a control winding to vary the flux level in the core and thus change the reactance of the power carrying winding .

The photo in the recent post is most accurately called an electromagnet. It has two terminals and one current path only.
It is not able to be a "transformer" until it is placed to couple a signal into another conductor, by means of it's magnetic field, such as a winding or a magneto coil. By itself, it is simply an electromagnet.

 

A "coupled inductor" that is not a transformer in any form is commonly referenced as a SATURABLE REACTOR, or MAGNETIC AMPLIFIER. It uses a DC current in a control winding to vary the flux level in the core and thus change the reactance of the power carrying winding .

The photo in the recent post is most accurately called an electromagnet. It has two terminals and one current path only.
It is not able to be a "transformer" until it is placed to couple a signal into another conductor, by means of it's magnetic field, such as a winding or a magneto coil. By itself, it is simply an electromagnet.

wouldn't pulses of positive voltage still be ac?

 

wouldn't pulses of positive voltage still be ac?

Originally, DC stands for Direct Current, AC means Alternating Current.

Today, it has other meanings in describing signals.
DC means signals at 0 Hz.
AC means signals above 0 Hz.

Pulses have both DC and AC.

 

wouldn't pulses of positive voltage still be ac?

Repetitive pulses can probably be called AC, although if there is no polarity reversal it is a bit of a stretch. Calling it a "repetitive DC pulse train" would be a more acurate description. What would add to any confusion is that passing the pulse train thru a transformer will produce what meets the definition of "AC" because the voltage out of the transformer will be alternating polarities. (How about THAT for adding a bit of confusion to the discussion??)

 

passing the pulse train thru a transformer will produce what meets the definition of "AC" because the voltage out of the transformer will be alternating polarities.

And a little more confusion, as there is an exception to that.
A pulse transformer is designed to output unipolar pulses with only a small reverse polarity undershoot at the end of the output pulse for pulses within its operating specifications.

 

Yes, this is all about semantics, but some very important semantics. I don't feel this is entirely artificial.
I have mostly encountered this discussion as regards flyback "transformers", and I think it would relate to Fly-buck as well.
If you talk about flyback transformers, most people know exactly what you mean and it is effective communication. On the hand, many people refer to these same items as coupled inductors. The reasoning for this is all about the function. In most respects flyback transformers look almost exactly like "regular" transformers except they function by transferring energy to the core, then in a separate step from the core to the secondary. So it functions like two separate inductors that transfer energy to each other through the core.
Another magnetic that looks like a transformer but works as a coupled inductor is the magnetic used in SEPIC converters.

There are other differences of course between flyback and forward converter transformers, but the point is it gets complicated very fast. Occasionally a wound device is intended for one type of application but can actually be used effectively in different circuit types. I agree this can be confusing and frustrating but I don't think a single naming convention solves the problem. Once we give something a name, many people assume it cannot be used in other ways.

As vague and frustrating as this can be, I encourage users to carefully consider how their magnetic device is to be used and not get too hung up on the name as that can really limit your choice of solutions.

 

My recollection is that ORIGINALLY a FLYBACK transformer collected the energy left over from a horizontal deflection pulse from a CRT deflection coil. ften the failure was in the plate circuit winding, due to an insulation breakdown. The failures were very seldom in the high voltage secondary.
I wonder what the primary failure mode has been since monitors became transistorized. My guess is that deflection systems changed a bit, and I was no longer involved with CRT monitor service at all.

 

well ok it is possible to have a single coil transformer but it is still not the most basic type, nor is it as common when compared.

... as this would be defined as a tapped inductor

This single-winding transformer is called an auto-transformer.

Inductors store energy to perform their function. Transformers do not store energy to perform their function, they pass energy from one port to another by means of magnetic induction.

 

through life, there are many books on electronics that I see calling a transformer an inductor.

I understand a choke, and how it's different in that it is wired and what it does. i understand that the difference between a transformer and an inductor is that a transformer induces current into one coil by charging another, while an inductor is just the coil itself.

but here in this picture is an example of what is unmistakably a transformer, which depending on windings will result in a different or similar voltage, yet the book describes it not as a transformer but an inductor. Even in classes I've taken the instructor is empty handed with reasonable answers that can apply in a logical sense with this question.

Why is it that in some settings, particularly in power supplies, these transformers are called inductors, not in a casual way, but 100% of the time by the text? They are inductors, sure, in the sense that there are some in it, of course all transformers are composed of a specific arrangement of inductors, but calling a transformer an inductor is a casual thing to do, not a textbook thing to do. textbooks subject to professional educated review should use the words that are most correct, clear, and comprehensive. "hand-wavium" is ok in some settings, but university level textbooks using the word should mean that the definition of the word includes that application, or else that the textbook should be using a different word.

Therefore, there MUST BE a very specific definition that makes this example not a transformer, but an inductor instead, what is it? Is this just an example of bro-ism that just won't die? Or is this a technical definition that somehow never made the dictionary?

This book is "switching power supply design" by Lazar Rozenblat. Without a doubt, I have had test questions marked wrong for calling a transformer a transformer, which means that he calls it an inductor because he wants a job. Is this some kind of illuminati conspiracy, is the dictionary wrong, or exactly what is the difference between a transformer and a transformer when in a power supply? View attachment 367902

Weather it is called a transformer or inductor depends on how it is applied. A transformer passes power through it,from source pressure to primary length of field as it changes to the secondary length of field and into its load.
An inductor or sometimes refer to as a coupled inductor, stores energy in the core for a period of time,then delivers it to a load at a later time.