Does anybody knows what kind of diode is it in the picture?

SamR

Joined Mar 19, 2019
1,479
Welcome to AAC! A little wider picture of the ckt board and maybe a make and model# of the equipment might help. It could be thingamabob's cousin thingamajig.
 

SamR

Joined Mar 19, 2019
1,479
I'm not sure that whoseywhatsey is a diode without a better look at the ckt bd. Not at all familiar with its markings... No diode band or LF markings...
 

SamR

Joined Mar 19, 2019
1,479
Since it is missing a diode band and is marked D on the ckt bd, quite likely a bidirectional transient voltage suppressor? I don't recognize the logo. And please forgive our bit of craziness. Seems cabin fever is rampant today...
 

DarthVolta

Joined Jan 27, 2015
159
Lucky for us they mark anything. For SMD cap's, I wish they'd add some color code, even if it was just for the ranges pF, nF or uF

So below what size SMD does no one bother to mark anything ? I'm not looking forward to trying to solder stuff on some motherboards I have.
 

MisterBill2

Joined Jan 23, 2018
4,475
If it's a diode, it's strange that it doesn't seem to have any polarity indication.
This is true! All of the diodes that I have seen have some indication of polarity so that they can be installed correctly. So now I am asking why you are calling it a diode? I mean, aside from the fact that the tag on the PCB calls it D2A?
And apart from those failed attempts at being funny, some of the participants will try to provide a useful answer.. A larger view of the PCB area will help us gain some context and possibly even help arrive at a useful answer.And now that I see that it is between the drain and source connections of a mosfet, it does seem that it may be a non-polarized varistor, a device intended to start conducting when the terminal voltage exceeds some limit. An unfortunate characteristic of varistors is that sometimes once they start conducting they keep conducting, much like a short circuit, and with the same effect. So I am presuming that the circuit is no longer functioning as desired, and that the resistance across this device measures some low value. Is this correct? Can you give us the number on the mosfet, please?
 

MrSoftware

Joined Oct 29, 2013
1,601
We definitely need to see more of the PCB, and any other info about it that you might have.

For the record, as mentioned above, there are bi-directional diodes of various kinds that do not have a specified polarity. The symbol will look something like this (this is a bi-directional TVS diode symbol):

upload_2019-9-9_21-27-50.png
 

MisterBill2

Joined Jan 23, 2018
4,475
Thanks a lot!
This is my first experience in this forum and I will recommend to other friends.
... and people here are funnyyy!
I did not consider those answers very funny. I take providing answers quite seriously, and when there is not enough information I let them know, rather than making random suggestions based on guesses, and if I do make a guess, I say that it is a guess, based on some stated presumptions. Poor advice is worse than no advice at all.
 

Thread Starter

mtcs

Joined Jan 21, 2019
10
I did not consider those answers very funny. I take providing answers quite seriously, and when there is not enough information I let them know, rather than making random suggestions based on guesses, and if I do make a guess, I say that it is a guess, based on some stated presumptions. Poor advice is worse than no advice at all.
I mean "people funny" and not " funny answers "...
 
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