What Is So Special About a Flyback Transformer?

RE: What Is So Special About a Flyback Transformer?

shabaz — Wed, 01 Nov 2023 22:45:39 GMT

Back to the tech, slightly related but only partially. Circuits related to magnets, induction and related circuits make fun things for kids to do.

This is a kids experiment (I'm still working on it). There's about 50 turns of wire on a bobbin, and kids can see an LED light up when the magnet is moved towards or away, but not when it's stationary. Similarly if a power supply is connected to the other winding on the bobbin, then the LED only lights up when power is switched on or switched off.

Happy to write this up sometime if there's interest, but I'm sure there will be a lot more interesting stuff from the experimenting with Flyback transformers challenge.

This is a crude circuit, simply to cut costs (like down to $1-$2 per board).

RE: What Is So Special About a Flyback Transformer?

michaelkellett — Mon, 30 Oct 2023 09:54:01 GMT

I've seen the comment that

"Energy is stored in the core's gap. It is then released to the secondary, which powers to the load."

But I don't think it really explains why transformers for flyback converters usually have gaps.

https://en.wikipedia.org/wiki/Flyback_transformer

Links are broken in this Wiki but you can find the key one here:

https://www.electronicdesign.com/content/article/21186397/why-have-an-air-gap

Discussions about where the energy is actually stored get too esoteric for me:

https://physics.stackexchange.com/questions/171955/how-does-an-inductor-store-energy

But I'm pretty sure it isn't actually stored in the gap else you wouldn't need to use bigger cores for more power !

RE: What Is So Special About a Flyback Transformer?

misaz — Sun, 29 Oct 2023 18:05:25 GMT

There is one guy guy on the youtube who provided analysis (review) of tons of USB phone chargers, so they may be interesting for challengers. Many his videos contains description of various flyback topologies as well as measurements on these circuits. Here is some example how flyback power supply should NOT look like

[View:https://www.youtube.com/watch?v=pYasc-9BKGg:640:360]