signal diode reverse voltage breakdown

[large_ghostman]

hi i was wondering say you have a small signal diode like the 1n4xxx and you exceded the reverse voltage and destroy it do they tend to fail shorted or open?? i only ask as i am messing with inductors so i am hopeing they fail open

 

[Reloadron]

Unfortunately they generally fail as a short. Now, if there is enough current available then after a short the diode can burn itself open. However, to answer your question they fail as a short. Bummer huh?

Also for what it is worth diodes like the 1N4001 to 1N4007 are classified as Rectifier Diodes rather than small signal diodes. Diodes like the 1N4148 or 1N914 would be more inline with being small signal switching diodes.

Say Hi to your dad!

Ron

 

[large_ghostman]

its a 1N4148 i was thinking of, yeah is a bit of a bummer guess i will have to watch my voltahe thanks for that and dad says hi back

 

[KeepItSimpleStupid]

Reverse breakdown is non-destructive, IF the current is limited. Think how a Zener diode regulator works. A diode usually shorts when it fails.

 

[large_ghostman]

all i am doing is putting different pulses through a diode into a inductor then a elec cap this is then through a large resistor to ground, just experimenting with inductors but i didnt want any nasty spikes coming back into dads exspensive signal generator (using dads as i dont want to foof up mine )

 

[Mr RB]

Hi Little Ghostman, re the 1N4148 I have a zener diode tester which provides up to 200v Dc at about 0.3mA, and it is made from an old moving-needle type multimeter which has a 200v full scale.

I use it to see what voltage zener diodes are without having to decode their numbers or colours. It's very handy to sort zeners out to put in drawers.

When touching a 1N4148 or 1N914 diode on the tester they "zener" quite nicely at about 140-150v. By "zener" that means they start to gently break down and leak current at over 140v. They don't seem to harmed by that, at least not at the 0.3mA and exposed to 150v for a couple of seconds.

 

[dr pepper]

Used my dads generator.

I like it.