How much would it hurt if a 2n3904 - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 16, 2019, 04:28:21 pm
content: For example if u hold a small TO-92 2N3904 in your fingers, and feed it enough current to explode it, or enough voltage, etc how bad would that be if u hold it ?With say under 30V 10A, a typical bench supply. I don't plan on doing this, just wondering.I suppose I could test it a bomb calimeter, or on test materials, but that would take a lot more effort. All tho it would be fun, IDK...

author: jmelson
author_rank: Super Contributor
timestamp: February 16, 2019, 04:33:57 pm
content: I can tell you! It will hurt plenty, for several days at least. The 300 W you mention will not explode the part, it will just get extremely hot. It probably takes several KW, for a few ms, to actually explode even a tiny transistor. I have made the mistake of grabbing parts to see if any were getting hot, and then regretted it!Jon

author: unitedatoms
author_rank: Frequent Contributor
timestamp: February 16, 2019, 04:34:16 pm
content: Please wear eye protection. But limbs are somewhat replaceable. The explosion will send shrapnel few meters max, so you will surviveedit: you will be inhaling purest silicon vapor possible, may be with traces of silan and unique organic copper composites yet unknown to general public. Tell us what superhuman side effects will follow the experiment

author: Ian.M
author_rank: Super Contributor
timestamp: February 16, 2019, 04:41:21 pm
content: If you pump kiloamps through it to explosively vaporise the die and bond wires, I'd bet on severe burns to your hand with maybe enough energy in the explosion to take part of a finger or two off. At lower currents the odds are it will get red hot long before it explodes, so the damage would depend on how long you are dumb enough to hold it for.If you want to experiment, you'll need some sort of high energy capacitor discharge rig, and a polycarbonate or other impact resistant plastic blast shield.

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 16, 2019, 05:20:14 pm
content: OK not something to do any time soon in my bedroom. Yeah and checking transistor temp's by touch, do at own risk everytime.What about with a 9V battery blowing up a little transistor ?

author: alex.martinez
author_rank: Contributor
timestamp: February 16, 2019, 10:40:20 pm
content: Quote from: lordvader88 on February 16, 2019, 05:20:14 pmPossible, we biased a 2n2222 in the wrong way once in high school. It sparkled and a piece hit a classmate. Pretty fun.

author: bd139
author_rank: Super Contributor
timestamp: February 17, 2019, 08:42:17 am
content: I’ve burned myself numerous times on hot transistors. You get used to it.If you want one to explode a 2n3904 the best thing you can do is connect a decent sized charged electrolytic cap across C-E and then forward bias BE with a 9v battery (no series resistor). They go bang then.Most of the time they just crack in half and smoke comes out if you seriously overload them though.Wear eye protection when firing up such a thing.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 17, 2019, 03:11:55 pm
content: I blew up some leds when I was young but most were by accident.You happen to have a 30V power supply with big elco's (something cobbled together) and then connect a led without series resistor because you don't know any better.Some people like to stick firecrackers in their mouths or anuses (plenty of youtube vid's) but I do not understand such behaviour, but I'll gladly give them the Darwin Award.Instead of having transistors explode it is far more interesting to examine the paremeters at the extremes of their operating ranges.What happens to a transistor when it gets really hot (but still works).What happens if you put too much voltage on a resistor (More than stated in the datasheet).What happens if you put too much current through a resistor?And ask yourself what happens, and why, and what you can do with it and learn from it.

author: kjr18
author_rank: Regular Contributor
timestamp: February 17, 2019, 04:31:37 pm
content: Some years ago I used a transistor to limit the current for brushless dc fan in my "lab power supply". I think it was something like BC547 or something like that. I noticed that after a while a fan was spinning faster, turns out that when transistor was getting warmer, it was allowing for more current to flow. So maybe when tested with higher temperatures you could invent free energy deviceSome time ago I found this on YT.

author: CJay
author_rank: Super Contributor
timestamp: February 18, 2019, 11:12:16 am
content: Can't answer for a 2N3904 but a colleague still has the scar from a tantalum capacitor that exploded between forefinger and thumb, he was squeezing it to demonstrate how the whistling sound it was making changed under pressure.It was in a Compaq Portable PSU that he was repairing and he's lucky he didn't lose an eye.

author: Cnoob
author_rank: Regular Contributor
timestamp: February 18, 2019, 11:50:14 am
content: QuoteI was taught about aboslute ratings using an AC128 and it's the only transistor I remember it's IC max current of 1Amp before thermal runaway kills it. (You have time to switch off power before you kill it.)

author: Refrigerator
author_rank: Super Contributor
timestamp: February 18, 2019, 10:15:26 pm
content: Quote from: kjr18 on February 17, 2019, 04:31:37 pmThat's kind of sort of how thermoelectric generators work.