I2t. What? Why? When?: The electric fuse case

[@zakirhussain6157]

I have searched a lot about the concept of I2t and I didn’t understand. However, I understood now partially. I will watch your video again and again because I am slow learner. Thanks for the video.

[@sambenyaakov]

Glad it was helpful!

[@clems6989]

Remember the fuse is current operated. However we are concerned with power. We just use current as an indicator because voltage is relatively constant. The Golden Rule of any physics: Nothing Happens in "0" Time !

[@Chris_Grossman]

Thank you for the theory behind fuses. I have never looked into this. Your talk has inspired me to download and read the Kaufmann paper.

[@sambenyaakov]

Thanks for sharing. The paper is old but still an eye opener.

[@electronichome1153]

Finally a good video regarding the melting integral I²t! Thanks Mr.Yaakov, again!

[@sambenyaakov]

👍🙏

[@power-max]

I always pondered about modeling a thermal breaker or fuse using a single RC circuit like this and using a low-pass filter of current flow through a shunt and a comparater controlling a pass transistor to make an active fuse, though such chips already exist of course

[@sambenyaakov]

Yes, ST just came out with a controller. But modeling is still important😊

[@Zetex2000]

Thank you for video. Very interesting and new stuff for me. I always wondered as a kid, why a 1A doesn't melt at 1A. felt like a scam 😂

[@sambenyaakov]

Better than being electrified as I was as a kid🤣. You may be surprised, but many engineers think that a 1A fuse will blow at a little above 1A or that it can protect a MOSFET against overcurrent.

[@MegaMoriarti]

Thanks for your explanation

[@sambenyaakov]

So nice of you. Thanks

[@MegaMoriarti]

Could you model the positive thermal coefficient of the fuse wire, I think the RT region could look like different @@sambenyaakov

[@sambenyaakov]

It can be done by a variale resistor of course. Yes, it might change the shape. This is home work.

[@mojiiim.r9446]

thank you ❤

[@petarsimic4097]

great video! as always...

[@sambenyaakov]

🙏🙂

[@tamaseduard5145]

👍🙏❤️

[@sambenyaakov]

🙏😊👍

[@analoghardwaretops3976]

Considering the case of open loop voltage mode PWM smps..the inverse...i.e. I (current) ×√time (in secs) (1000*1000u secs) can be implemented similarly for a
" pulse by pulse" protection thereby emulating the actual I^2t function.....
Please share your comments on this..

[@sambenyaakov]

Thank you for comment, but I don't follow. Please eleborate.

[@analoghardwaretops3976]

@@sambenyaakov existing V. mode pwm usually have "peak" C.L. as a protection feature..this is on a pulse by pulse basis.....in an over current fault situation, where over an extended period of time..if this is active..the I^2t of the device or load may be still exceeded, eventually leading to some failure...
therefore my reasoning is if such similar protection can be implemented in pwm control , with I(avg/rms)*√t.. ,
since I is in A/mA and t(on) is in uSecs.
such may be easily done with transistor/opamp circuits..