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My N channel mosfet burn or not

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baby_1

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Hello
i test my mosfet with this bias


but after that it works find and turn of when i turn off my battery it doesn't turn off and when i give the negative voltage -10 to his gate but it doesn't work.i can't turn off it?

it is burn?why?
 

it will be burned...... You have to keep a free wheeling diode across the inductive load for discharging. Since there is no such path, the total reverse voltage will be appearing across mosfet and it will burn.
 
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    baby_1

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As Jushoraj suggested, You must also know the Gate to source break down voltage.
 

Thanks
but i tested it my diode to protected my mosfet but it burned again
 

I don't see a way for this mosfet to burn unless you use a Vgs higher that the maximum allowed (usually 15-20v) or a high source-drain voltage or current.

I think the problem is that you are not using a pull down resistor to ensure that the gate is pulled down and the mosfet stays off (a 10k resistor between source and gate is fine).
You shouldn't leave the gate floating because you can get random switching or half on state.

Alex
 

Thanks Alex.
as i explained i use negative voltage an use a 1k and 10K ohem to netagtive resistor at gate of mosfet.but it doesn't turned off.
 

You may have explained it but I didn't understand anything from what you described:
but after that it works find and turn of when i turn off my battery it doesn't turn off and when i give the negative voltage -10 to his gate but it doesn't work.i can't turn off it?
Click to expand...

and you last description is still confusing
i use negative voltage an use a 1k and 10K ohem to netagtive resistor at gate of mosfet.but it doesn't turned off.
Click to expand...


Do you have a schematic of what you describe?
 

Vgs higher that the maximum allowed (usually 15-20v) or a high source-drain voltage or current.
Click to expand...
Thats correct , Sorry I din't check spec.
Since there is no such path, the total reverse voltage will be appearing across mosfet and it will burn.
Click to expand...
This statement is completely true and the MOSFET will burn.
Say once the MOSFET is on inductor will store the energy, and as soon as MOSFET gets off, there will be no path for inductor current to flow and drain voltage of MOSFET will increase to very high voltage more than break down(>>100V).
 

Which inductor are you referring to, I only see an incandescent light bulb connected to 24v.
I think we need a schematic , at least I do because I have no idea what we are talking about apart from a couple or resistors in the gate and a negative bias.
 

Hi
The bulb that you have used is 12 volts , right ? ( the text nearby your bulb ) . so VDC is 24 v. right ? what this means ??!!
And another thing : did you drive it with a DC voltage across the GS , really ? or perhaps a pulse train ?
Best Luck
Goldsmith
 

inductor are you referring to, I only see an incandescent light bulb connected to 24v.
Click to expand...
Original poster has to clear this. I understood, L1 inductor of 12V, 2A. If it is bulb then no problem.
 

THe BOdy Diode can handle rate DC current of switch. If used in PWM mode.. greater than this.. add a bigger diode. Also have you practised safe EOS/ESD practises in all connections to battery and parts.. EMC is critical part of design.
 
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    baby_1

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it doesn't related to gate that doesn't have any resister to limit the current?
 

Device appears to be non-functional.:sad:. Did you practise ESD safe methods? You have only a little protection for ESD damage on connections.:roll:
 

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