Discharge needle under the common mode inductor

eeko2005

Discharge needle under the common mode inductor [Copy link]

I checked a lot on the Internet, and they all said that the discharge needle is to provide a discharge circuit, and discharge through the air when high voltage is applied. It is relatively easy to pass EMI.

But what is this discharge circuit like? I still can't figure it out.

In the same way as common mode inductance, after discharging through the discharge needle, when high voltage is applied, doesn't it directly transmit the high voltage to the load? How to discharge???

Let the load directly bear high voltage to discharge? ? ? It doesn't make sense!

qwqwqw2088

Does it feel unreasonable?

You can learn that there is a device called a discharge tube, the principle is the same

A method for EMC testing

It only provides a discharge circuit and does not suppress common mode.

topwon

ESD与PCB布局.pdf (168.19 KB, downloads: 283)

2019-6-25 11:13 上传

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Online information is for reference only.

eeko2005

qwqwqw2088 posted on 2019-6-24 22:05 Does it make sense? You can learn about a device called a discharge tube. The principle is the same. One method of EMC testing is just to provide a discharge circuit...

I know what a discharge tube is. When one end is grounded and the other end is at high voltage, it provides a low-resistance circuit to the ground to discharge energy.

I also know that the discharge pin is not used to suppress common mode.

What I don't understand is that the common-mode inductor is conductive on the same side. Even if a discharge needle is added to break through the air, where is the loop? It is different from using a discharge tube. The common mode is followed by a load, not the ground... How to discharge the energy?

eeko2005

I asked about this discharge needle

eeko2005

topwon posted on 2019-6-25 11:14 Online information is for reference only.

This is good, it makes sense.

dqp05

topwon posted on 2019-6-25 11:14 Online information is for reference only.

Good information, thank you

有时候

topwon posted on 2019-6-25 11:14 Online information is for reference only.

So if the input line has a ground wire, then we don't need to consider using the discharge needle.

topwon

Sometimes published on 2022-1-7 16:28 So if the input line has a ground wire, then we don’t need to consider using the discharge needle.

I think so, but the premise is that the input ground wire can reliably protect the position of your output terminal. For example, the output terminal is placed at the opening of the metal conductive plate and is reliably connected to the ground wire to shield and discharge static electricity introduced from the outside.