# Difference between Surge, ESD and EFT

I was going through this ESD Presentation where I noticed the below image:

I'm trying to understand the different types of overvoltage and they have given the classification above. In this, what I don't understand is that the current for the surge is given as 100 / 1kA and the pulse energy is given as 10 / 80J. Can someone tell me what is the meaning of those values? Like how should I interpret them?

Also, why is the rise time not applicable for EFT burst?

I would be grateful if anyone can provide me with a diagram for the explanation.

• Try computing energy from voltage, current and duration. Commented Feb 8, 2023 at 7:17
• I do not understand. Could you please help on how to understand the current and power column?
– user220456
Commented Feb 8, 2023 at 7:21
• I don't see a power column. What is there to understand about current? It is charge per time. Commented Feb 8, 2023 at 7:30
• @greybeard, what is the current value when it is mentioned as 100 / 1kA? Like, why have they mentioned in such a fashion, where they could have mentioned as a single whole number?
– user220456
Commented Feb 8, 2023 at 7:46
• A surge is a longer fluctuation in voltage, usually a voltage drop. "EFT" is apparently something made up by the "Lets Invent Abbreviations For The Heck Of It Club" and it just means fast transient in plain English. ESD is also a fast transient but usually modelled as coming from humans ("human body model") with standardized values. Commented Feb 8, 2023 at 7:59

what I don't understand is that the current for the surge is given as 100 / 1kA and the pulse energy is given as 10 / 80J. Can someone tell me what is the meaning of those values? Like how should I interpret them?

The number in the table specifically says this: 100÷1k A and is certainly confusing. It is trying to state a peak current range from 100 amps to 1,000 amps but it's doing so in an obscure way. The same for the cell that says 10 / 80J.

The reason why there is a range of applicable surge currents is because they are likely indirect lightning surges and, the relevant specification (EN 61000-4-5 for example) has several peak voltage levels ranging from 500 volts to 4 kV and several different output impedances (applicable to the specific ports on the piece of equipment to be tested) in the range 2 Ω to 42 Ω.

Also, why is the rise time not applicable for EFT burst?

An EFT burst is very fast (circa 6 ns) and, this rise time is massively influenced by virtually any wiring it connects to that it's easier just to write N/A.

I would be grateful if anyone can provide me with a diagram for the explanation.

I can't think that a diagram is useful here but, I can show the EN 61000-4-5 surge voltage table: -

I took the above table from a TI support forum because it nicely summarises the peak voltages, the range of output impedances and the peak currents into a short circuit. I've put a red box around the range that is commonly applicable.

• Thank you for the answer!
– user220456
Commented Mar 24, 2023 at 9:49
• ÷ is not too uncommon to denote spans in some circles/locales. Commented Mar 24, 2023 at 11:18

Surge, EFT and ESD are three classes of standardized disturbances in terms of IEC 61000-4-X compliant conducted immunity EMI testing. These standards also define the impedance of the diusturbance.

Surges simulate a major mains voltage excursion, so the impedance is very low and allows for tremendous currents, because your device is directly wired to the interference source.

EFT bursts are just several EFT events every couple of ms, so the single EFT specs apply.

• Thank you. But please explain the marked current values?
– user220456
Commented Feb 8, 2023 at 8:34
• what is the current value when it is mentioned as 100 / 1kA? Like, why have they mentioned in such a fashion, where they could have mentioned as a single whole number?
– user220456
Commented Feb 8, 2023 at 8:35
• @Newbie all these interferences come in different "classes", which differ by the interference voltage. More voltage creates more current and correspondingly more energy. So depending on your application demands, you define which class you want your product to satisfy, i.e. you might not have to be compliant to the extreme values given in this table. Commented Feb 8, 2023 at 8:36
• @Newbie Ah I see your confusion. the ÷ symbol doesn't indicate division here. It is commonly used to give a span. Commented Feb 8, 2023 at 8:41
• could you please tell me how to understand that parameter?
– user220456
Commented Feb 8, 2023 at 8:51