Where is the same name end

aq1261101415

Where is the same name end [Copy link]

 

Hello everyone, I have a question. As shown in the figure, if I connect 2 and 3 together, how do the new same-named ends correspond? Is 1 corresponding to 5 or 4 corresponding to 5?

maychang

[As shown in the figure, if I connect 2 and 3 together]

If the number of turns of windings 1~2 and 3~4 is the same, then after 2 and 3 are connected together, the inductance between 1 and 4 is close to zero.

maychang

[As shown in the figure, if I connect 2 and 3 together]

Therefore, we should use windings 1~2 and 3~4, and never connect them like this.

maychang

Your transformer seems to be a flyback switching power supply transformer. If it is indeed a flyback switching power supply transformer, then windings 1-2 and 3-4 are likely to be wound on the innermost and outermost parts of the core, while windings 5-6 and 7-8 are sandwiched in the middle. This winding is to reduce the leakage inductance between the primary and secondary.

maychang

To connect the two primary windings in series, windings 1~2 and windings 3~4 should be connected end to end. They must not be connected end to end or end to end.

aq1261101415

maychang posted on 2023-11-14 14:57 [As shown in the figure, if I connect 2 and 3 together] Therefore, we need to use the two windings 1~2 and 3~4, and never connect them like this.

So I would like to ask you, this is indeed a flyback switching power supply transformer, how should it be connected? Should 4 and 2 be connected together, 1 pin connected to the positive power supply, 3 to the D pole of the MOS tube?

maychang

aq1261101415 Published on 2023-11-14 15:45 So I would like to ask the seniors, this is indeed a flyback switching power supply transformer, how should it be connected? Should 4 and 2 be connected together, 1 pin connected to the power supply positive, 3 ...

[This is indeed a flyback switching power supply transformer. How should it be connected? ]

Because the 5th pin of the transformer has been connected to the positive end of the rectifier diode, the 1st pin of the primary should be connected to the positive end of the power supply, the 2nd and 4th pins should be connected together, and the 3rd pin should be connected to the drain of the MOS tube.

maychang

aq1261101415 Published on 2023-11-14 15:45 So I would like to ask the seniors, this is indeed a flyback switching power supply transformer, how should it be connected? Should 4 and 2 be connected together, 1 pin connected to the power supply positive, 3 ...

Strictly speaking, there are some rules for which winding 1~2 and winding 3~4 should be placed outside and which inside. Generally speaking, the outermost layer of the winding should be connected to the positive terminal of the power supply, and the innermost layer should be connected to the drain of the MOS tube. This connection will have less interference to the outside world.

aq1261101415

maychang posted on 2023-11-14 15:56 Strictly speaking, there are some rules for which winding 1~2 and winding 3~4 should be placed outside and which should be placed inside. Generally speaking, the outermost layer of the winding should be connected to the power supply...

OK, thank you senior. I feel that transformers and inductors are the most difficult things to understand.

lansebuluo

If 2 and 3 are connected together, will they cancel each other out? Why is this done?

maychang

aq1261101415 posted on 2023-11-14 16:54 OK, thank you senior, I feel that transformers and inductors are the most difficult things to understand

[I feel that transformers and inductors are the most difficult things to understand]

Nothing. Inductors and transformers just involve some knowledge about magnetism, which is much easier than bipolar transistors or field effect transistors.

aq1261101415

maychang posted on 2023-11-14 19:26 [I feel that transformers and inductors are the most difficult things to understand] Nothing. Inductors and transformers are just related to the knowledge of magnetism, which is more difficult than bipolar triodes...

Huh? No way, everyone around me says that inductors and transformers are the most difficult things to understand? And I myself also find it difficult to understand, and I think bipolar transistors or field effect transistors are easier. How can you embarrass me?

aq1261101415

lansebuluo posted on 2023-11-14 18:16 If 2 and 3 are connected together, will they cancel each other out? Why is this done?.............................................

should be

maychang

aq1261101415 posted on 2023-11-15 11:18 Ah? No way, everyone around me says that inductors and transformers are the most difficult things to understand? And I myself feel that it is difficult to understand, but I think bipolar and tripolar...

For inductors and transformers, you can touch the windings, the core, and the insulation, but for transistors, you can’t. So, when using transistors, you follow the datasheet, and there are only a few basic parameters, but when using transformers, you have to design them yourself, and there are too many parameters that can be adjusted. Especially for integrated circuits, you don’t know what’s inside, and you don’t need to know, just use it according to the datasheet.

fjdeepblue

2,3 are connected together, if the number of turns is equal, then they will cancel out completely.

aq1261101415

fjdeepblue posted on 2023-11-15 15:12 2,3 connected together, if the number of turns is equal, then they will completely cancel each other out

Yes

aq1261101415

maychang posted on 2023-11-15 14:57 For inductors and transformers, you can touch the windings, the core, and the insulation, but you can’t touch the transistors. Therefore, using transistors is the root...

I see. This is the difference between component designers and component users.