DIODE QUERY

[prateeksikka]

Hi all.

I want to know ,what will happen if we short the 2 terminals of a diode?
will the current flow?

what i suspect:

Current will flow for some time till charge concentrations equate and diode is destroyed .....
i.e its functionality gets over....

 

[indulis]

If you "short" a diode, it will never "turn on". If it never turns on, no current will flow through it and all the current will flow through the short. In other words, no the diode will not be destroyed.

 

[MP1]

However......if the diode is in-circuit and powered up when you short it, you run the possibility of letting the smoke out....  ;D

MP

 

[mvs sarma]

MP,  how came to such conclusion?  the circmustances to be elaborated where from smoke comes?

1. yes if the diode is in the shunt path like that in an smps with forward mode --

2. a. yes if one diode of a bridge is shoted-- b. if the diode of anhalf wave rectifier type adopter is shorted, the electrolytic filter cap blows due to -ve half cycles.

sarma

 

[MP1]

sarma,
Thanks for the elaboration, but I was actually making a joke based on the old electronics addage that all electronic components have smoke in them and if you let the smoke out, they will stop working... of course, we all know that this is not where the smoke comes from.

MP

 

[mvs sarma]

FINE MP

i am reminded of FOOL or JOKE circuits that used to apper in the Summer circuits edition of ELEKTOR magazine (NL based)

there aslo we used to find one or two absurd circuits and an almost convincing write-up even-- i agree we need some lighter coner to relx

sarma

 

[abhishek gupta]

diode without any battery has no mean.any diode inividually is of no use. actually when u will short a diode then a depletion layer forms which prevent the flow of free charge carriers.so there will be no curent in diode.

 

[Cabwood]

Indulis was right, abhishek, and so since the diode has no voltage across it to cause charge depletion, the depletion layer has nothing to do with the absence of current in the diode.

 

[prateeksikka]

hi.so
what is the conclusion?
will the current flow through the short?if yes ,the diode will get depleted of its charge carriers and it will be destroyed .no?
what do u think?

 

[mvs sarma]

hai prateeksikka

plese think about your qestion.

is the diode a part any circuit or it is stand alone with no connections.
does yuor doubt belong to any specific circuit? if so which one.
what charge on the diode you are talking about ??
ALL Qs only is it not ? please moderate your question to be able to get a reply.

sarma

 

[MP1]

FINE MP

i am reminded of FOOL or JOKE circuits that used to apper in the Summer circuits edition of ELEKTOR magazine (NL based)

there aslo we used to find one or two absurd circuits and an almost convincing write-up even-- i agree we need some lighter coner to relx

sarma

I have never seen one of them. I don't mean to take this off-topic, but if you happen to still have one or more of these magazines, it would be amusing to see some of these joke articles. Of course, it should appear as a new topic.

MP

 

[prateeksikka]

HI.

My question is i have an open diode (not in any circuit) .I short its two terminals .
Will the current flow through the wire for first few nano seconds to equalize p and n carriers?

 

[audioguru2]

A diode is not a battery. It has a small capacitance that will hold a charge until leakage discharges it.

 

[prateeksikka]

hi audioguru!

even if we consider a diode as a capacitor in this reference ,what happens when we short circuit the ends of a capacitor?
will it not get discharged?why wont the electrons on n side move to holes on p side through the external wire?

 

[audioguru2]

The amount of capacitance of a diode is very small. The leakage current of a diode or surrounding circuitry would discharge its capacitance almost immediately.

 

[mugsby]

first off you'd have to overcome the forward breakdown voltage, with the diode shorted thier would be no potential differance to do this so nothing would happen.