MOSFET switching for an Inductor | Inductive spiking & Use of Freewheeling diode

[@vitaliyl7030]

Thank you for great videos. Small correction, for the free wheel diode the inductor energy doesnt go back to the supply but dissipated in the diode itself.

[@user-qr4jf4tv2x]

got it it was because of this time stamp 4:50

[@cesarcantoral6100]

You are very good at explaining complex processes...to the last detail . You make them easy to understand....great work ...

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@rhonielguillenredula2507]

As a practicing design engineer, just want to say thanks for the refresher bro!!

[@FoolishEngineer]

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[@jairo6001]

I have been searching for two years, and I can only understand your course very well. its 11:20PM I was planning to sleep, but now am not going to

[@FoolishEngineer]

Good for you!!

[@Derlis_Jara]

Beautiful grafics and explanation. greatings from Argentina.

[@FoolishEngineer]

Thank you! Cheers!

[@chanakasampath9138]

I did learn about dc to dc convertor through your vedios.Thank you very much.

[@FoolishEngineer]

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[@chanakasampath9138]

@@FoolishEngineer i am from sri lanka. Thanks your helps.

[@chanakasampath9138]

@@FoolishEngineer i am going to create pure sin wave inverter using sine wave oscillator, class D amp. and low pass filter, i need your help. Could you help me?

[@AshishYadav-ul8es]

your all videos are awesome, keep posting and best of luck for future

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@markscheutzow3446]

To me, that's a "damper diode", which probably dates me too well. You have an informative direct style I appreciate and recommend. 👍

[@rohanchoudhary6890]

Thanks for the informative video. But there is correction in waveform, when vgs is high at that time vds won't be 0 it will be equal to the external supply as inductor will become short circuit (constant current). So full external supply will be shared to vds of mosfet

[@sebaschtl9710]

Thanks it is just great. I learned it like a charm. It is perfect.

[@madtscientist8853]

That HUGE spike Of energy is the inductor wanting to oscillate You're preventing energy from doing what it Naturally WANTES to do instead of what you forced to do. That's why everything nowadays HEATS UP.

[@izzzzzz6]

I have two non expensive solar grid tie inverters. They cause a great deal of RFI. I am unable to use my radio equipment unless i disconnect them. I tried installing an inline filter but it makes very little difference. I also tried putting a large capacitor in parallel with the panels but no help there either. I actually came here for a different reason. Wondering if it would be possible to make an AC flywheel circuit for mains electricity. The concept 2 banks of electrolytic capacitors in different orientations with Zener diodes on each of them so they only charge once voltage goes above a certain value then they release the energy again on the down cycle. The idea being to buffer the ac mains voltage so when items are switching in and out they take that initial draw of power from the capacitors and not from the grid, thus helping the solar power smooth out peaks and troughs of power demand as devices switch in and out / on and off such as inverter hot plates for cooking as they cycle on and off.

[@sudheerkumar5966]

Very good sir For freewheeling theory. Thanks

[@FoolishEngineer]

Always welcome, thanks for watching!!

[@MaDrone]

Nothing new under the sun, cause the diode parallel, i.e. to the relay coil, is common since semiconductors was introduced, but very, very well explained. Good teacher.

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@ramagirikuna1586]

Outstanding sir.. ❤

[@ministeriomundialliberando8403]

Sinceres thanks for your lettures. But, why most half bridge topologies converter use just a resitor and capacitor to reduce the spikes during off time?

[@tonyrebeiro]

The voltage spike generated across the coil when the MOSFET goes OFF is the opposite polarity of the supply voltage. Therefore, the diode is conducting when this happens and dissipates this energy into itself and NOT as mentioned, into the supply.

[@danbmxs]

I want to replace the ignition system of my old car with a transistor (TCI) instead of a breaker point contact switch. is it necessary to also add a diode in this case on the ignition coil, to protect the transistor from damage. will it not affect the output of the spark plug flame

[@ElectronicsRETECH]

thanks for this video but i have a doubt that ,i have a gate driver circuit and i have also used a diode as u taught and iam still getting high spike after some time my simulation runs? why

[@sajjad213]

Why there is ringing across DS voltage after putting the diode?

[@samithetechsavvy6485]

thank you very much

[@FoolishEngineer]

You are welcome

[@alanleewaddell]

I was using inductors and high speed switching with a 27,000MHZ quartz crystal to create a swing for a Tesla coil and I was testing it with a dead 9v battery that had about 6v left in it and it went into a resonance cascade and it fried the whole ciruit also it wasn't hooked up to a coil yet .. but ya my goal was to creat a specific resonance only I got wayyyy more than I expected . If I can recreate it again it will be tricky to handle the continuing increase to find out far it can actually go without frying it again ,, not sure what to do next since it isn't ready for the coil or , maybe I need something else . I had originally thought I would create two circuits and apply them against each other with another crystal at 28,000MHZ to get the resonace started and then figure ways to adjust it provided it's close enough to correct parameters .. 🤔 I was able to run another circuit like it with an earlier SCR without it frying and it runs off of 5 v and of course the goal here is to keep it running after the 5 volts is gone if it can continue to remain regeneratively and if it can pull what it needs from the air and keep the LEDs lit up ....

[@ether936]

You likely created an uneven charge/discharge time in the ac cycle. Would be curious to see a circuit

[@TekCroach]

At 5:00, the description is somewhat flawed I think. The protection diode just dissipates the flyback voltage as heat without diverting it back to the main power supply.

[@wallypizza323]

Electronics seems like a game of chess mixed with magic the gathering. This has these basic moves. You pair this with that, and it has this unique move, but now it has a sudden weakness.

[@josepeixoto3715]

So true; mosfets, igbts, etc are not yet fully ready to be sold,still a kind of art... lol Every new Solution brings new problems.

[@josepeixoto3715]

Why don't i see that diode on comercial inverters? does it bring additional problems?

[@LEO22116]

You can show the drain-source capacitance to show where the inductor pushes it's voltage when suddenly turned off.

[@braydinjones582]

Great video! Any reason why I’d be getting a similar phenomenon when a solenoid is turned on. I see pretty significant spikes when I first turn on a solenoid and turn it off (with a button)

[@FoolishEngineer]

solenoid is a type of inductive load

[@braydinjones582]

@@FoolishEngineer Thanks

[@stephanc7192]

Great video

[@fourierv2]

Thanks for the nice video. It helps to explain about inductive spiking for switch FET applications but why does this then result in a ringing effect? Why not just a large spike and then the FET settles back to the supply voltage?

[@vbidawat93]

The ringing is because of the LC circuit that's formed with the output cap, now recall a series RLC circuit's step response. The R is summation of the dcr of the inductor, trace resistance, the source resistance in the path.. hope that clears your doubt

[@electrowashyelect9715]

The ringing effects comes from the collapse of the voltage spike

[@jaysunx1]

Im trying to use this aspect of inductors to create voltage spikes in a controlled fashion. How do I read the value of di/dt from the oscilloscope measurement

[@thebread8918]

Pls make a video about how a rc snubber works 🙏

[@HieuLe-nr6em]

Hello. I want to make a fake load circuit to test the battery that can adjust the current passing through, my idea is to use a mosfet. load directly from the mosfet. I hope you can help me calculate the tolerable capacity of the mosfet through its datasheet and how to dissipate heat for durable use. Thank you very much

[@atheist_happie]

I'm trying to make mosfet spot welder after blowing mosfets i searched alot about this failure and found voltage spike is killing mosfets this is my mistake to not knowing about mosfet properly after watching your video i found that my wires are inductive load which creates positive spike at drain so i need to place diode between mosfet's DRAIN (before wire bcz wire is inducing positive spike) to "+" Terminal Of My Battery. ANODE leg to DRAIN CATHODE leg to "+" terminal of battery. Correct me if I'm wrong?

[@electrowashyelect9715]

What about adding a capacitor of 47uf in parallel with the inductor instead of a fly wheel diode.

[@sisirmondal4670]

Good explain

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@vb9528]

great video thanks

[@za_ozero]

so instead of hitting a MOSFET higher voltage hits diode and then power supply? what if power supply is not ready for it too?

[@adarshmadhusoodanan2927]

Explained well

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@mr.faceless9335]

How to protect power supply against the current which will returned after FET's off? If I have 150 uH inductivity and 4 V 200 A power supply?

[@magnet2011]

The ending "thanks watching " great style,I watch full video 👍, sir what software you used to make your video

[@FoolishEngineer]

Thank you so much!

[@paulopcbs]

Very good!

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@electroquests]

When the MOSFET is OFF, the back EMF from the inductor will cause a current to flow through the diode and back to the supply, but in addition to that it can also flow through the inductor itself. So there will be two paths for current to flow, right?

[@FoolishEngineer]

I highly doubt that. I need to check on it.

[@pushpendraaryan5551]

When MOSFET is off then diode act as close switch for flyback voltage so diode short circuit to the inductor during this time period so current flow only in inductor not to power supply because ground path of power supply is not complete . During this time inductor and freewheeling diode will heat so generally one snubber circuit i.e. parallel combination of a resistor and a small value ceremic capacitor add in series with freewheeling diode.

[@electroquests]

@@pushpendraaryan5551 Yup you're right about the diode part. The circuit is actually complete, since the MOSFET has a body diode, the only thing is that the body diode will be reverse biased.

[@biswajit681]

@@electroquests stored inductor energy will be dumped into the diode

[@damirdze]

The inductance tend to keep the current in the same direction ( no change in the direction ). So it flows back to the source through the diode.

[@creativeideaseee]

Nice example

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@StefanStern145]

Hello, thank you very much. I have a question. Are the Spikes AC or DC inteferences?

[@FoolishEngineer]

DC

[@ovidius2000]

insteadADiode,IfWePutACapacitor,WhatHappens?

[@psanmuk]

Thank you

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@iracreativeworld8323]

Good

[@ayushsinghal6557]

can you also explain capacitive load with MOSFET? in Both side,,,capacitive load at the drain side and once in source side...thanks.

[@sivakrishna2822]

Please note a correction!..Energy can never flow to supply via freewheeling diode..

[@rajendrarajkumar6483]

your video is very usefully pl. hindi me banaye

[@FoolishEngineer]

Will try

[@biswajit681]

One additional points all power supply are not sinking type so you can put large electrolytic capacitor to sink the current when MOSFET is off

[@electroquests]

The capacitor could get damaged because the potential difference between the + of the back EMF (i.e. Voltage between the Drain and the Voltage Source when the MOSFET turns OFF) and the positive terminal of the voltage source will be large. So, we might need a very high voltage capacitor.

[@biswajit681]

@@electroquests no when freewheeling path is present at that time it will not damage the capacitor.. input voltage *2 rated capacitor is enough

[@RexxSchneider]

@@electroquests Once the diode is added to the circuit, the back emf can never exceed the positive supply by more than one diode drop (not more than a volt or so, worst case). You only need a capacitor with a voltage rating a few volts more than the supply voltage. You really need a return path to ground via the supply in any scenario, so you're going to put a capacitor across the supply in any case.

[@pavin1322]

Bro, please explain Complete details about gate driver circuit for mosfets

[@FoolishEngineer]

Definitely, working on it!

[@pavin1322]

@@FoolishEngineer thanks bro

[@ethansnow7110]

Sir, very nice course, but what if I polluted the power source by using the diode, how can I solve this problem then?

[@ramahwart7479]

Can I contact you via email for consultation about MOSFET Inductor Circuit? Thank you.

[@FoolishEngineer]

How can I help you?

[@ralphchen1125]

Is it safe for flowing back to power source?

[@FoolishEngineer]

Yes, upto some extend

[@salmansalu-be2ho]

❤

[@creativeideaseee]

May i know which software are you using to make the animation

[@FoolishEngineer]

after effects

[@hoanpham5862]

niceee

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@prerupa]

schottky diodes work pretty well in this application than fast recovery diodes.

[@qwertymnbvc-k9x]

huh??!! Vgs on = mosfet off???

[@electrowashyelect9715]

Kindly make a video of a capacitor instead of a free wheel diode

[@Korystuwatch42]

rubbish, the current does not flow trough diode back to the battery, it cuirculates inside of the inductor

[@thebread8918]

Actually It can do it, because spike Voltages from inductor has more potential than the battery that makes a circuit acting like a charge battery with 2 sources.

[@thebread8918]

At least that is what it supposed to be, if you know why it flows through the diode pls explain me 👍

[@Korystuwatch42]

@@thebread8918 if the mosfet is not damaged and fully closed there can be no current trough the battery. And if so, at least not in that direction

[@rolfmader2783]

pChannelTransistor-Diode false! Intern Bypassdiode ( = Z-Diode) protects it most!

[@kartinosurodipo4520]

The diode parallel to inductor will blow quickly 😂 This is not practical in real circuit