bigbat

maychang posted on 2022-4-23 16:05 Transformers are indeed something that is not easy to understand. In some cases, inductance can be compared to mass in mechanics. But transformers are so complicated...

I have been thinking about this question for a long time. First of all, I don't quite understand what electric current is. There seems to be an analogy that electric current is like a chain transferring energy. Electric current is the way electrons transfer energy. I think this is very similar. But electrons are so small, how can we see them? How do you prove that the electron that goes from A to B is the same electron? You may say: the electron moving in a vacuum must be the same, then what if I say that electrons are waves? It's just that this wave vibrates from A to B? I once thought that a laser beam will become larger after it propagates to a far distance. Will electrons also become smaller if they propagate to a far distance, like light?

maychang

bigbat posted on 2022-4-23 16:59 I have also thought about this question for a long time. First of all, I don’t quite understand what electric current is. There seems to be an analogy that electric current is like a chain transferring energy. Electric current is...

"First of all, I don't quite understand what electric current is."

Don't say you don't understand. When Joseph John Thomson discovered the electron, especially when Robert Andrew Millikan directly measured the electron's charge, physicists all over the world didn't quite understand. After Louis Victor de Broglie said that the electron is also a wave, especially after GP Thomson proved through experiments that the electron is indeed a wave, physicists all over the world were even more confused.

maychang

bigbat posted on 2022-4-23 16:59 I have also thought about this question for a long time. First of all, I don’t quite understand what electric current is. There seems to be an analogy that electric current is like a chain transferring energy. Electric current is...

Everyone agrees that electric current is the directional movement of electric charges.

The definition of current is I=dq/dt, where q is the charge passing through a certain cross section and t is time.

Here comes the problem: dq is an infinitesimal quantity, but the charge of an electron is not infinitesimal, it is a finite value. Since it is a finite value, it cannot be written as dq.

So, how do we define electric current?

maychang

bigbat posted on 2022-4-23 16:59 I have also thought about this question for a long time. First of all, I don’t quite understand what electric current is. There seems to be an analogy that electric current is like a chain transferring energy. Electric current is...

"I once thought that if a laser beam spreads far away, its spot size will become larger. So will electrons also become smaller if they spread far away, just like light?"

This is your analogy again.

A beam of light is not just one photon, but a rather large number of photons (at least 1^9 for reflected light visible to the human eye). The electron you are talking about is just one electron, not a group of them.

PowerAnts

Inductance is just a parameter in the real transformer model. The relationship between the subset and the parent set

zhsir

Dominoes

zhsir

The inductance of the transformer is very important when storing energy or participating in resonance. For example, in the flyback circuit, the transformer primary stores energy when the switch is turned on, so controlling the inductance is to control the amount of energy storage. In the LLC circuit, the primary inductance of the transformer often participates in resonance and needs to control the gain, so the inductance must be controlled. If it is just transferring energy, that is, when the switch is turned on, the transformer only transfers energy to the secondary, then the larger the inductance, the better, such as in the forward circuit.

jiang200385

Transformers are too complicated to be explained in one or two articles. The best and fastest way to understand is to make a physical object yourself to measure the cleavage. The greater the inductance, the higher the power. It is a matching parameter. Only when it is suitable can the output power be output, otherwise there is a high probability of the machine crashing.

bigbat

jiang200385 posted on 2022-5-30 13:34 Transformers are too complicated to be explained in one or two articles. The best and fastest way to understand is to make a physical object yourself to measure the cleavage. The larger the inductance, the smaller the...

Thank you, I have almost figured out the problem. The capacity of the transformer has nothing to do with the inductance. It is just that the inductance affects the capacity of the transformer, and the inductance is a parasitic parameter of the transformer. The inductance of the transformer coil must exist.

MrCU204

The output of the secondary side of the transformer is the self-inductance potential. When there is a load, the potential will be leaked and the current will increase. This is what reflected impedance is.

If the load is heavy, the magnetic field needs to be strengthened to support it. Reducing the self-inductance potential can introduce a larger current. This is a compromise.

MrCU204

Transformers and emitter followers are different in type but similar in style.

The reflected impedance on the primary side of the transformer and the voltage series negative feedback of the emitter follower can both create a dynamic balance.