Joy of exploding circuitry

Discussion in 'General Electronics Chat' started by steinar96, Apr 24, 2009.

  1. steinar96

    Thread Starter Active Member

    Apr 18, 2009
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    I was wondering if anyone else gets a kick out of seeing your components blow up into bits.

    Was fooling around with a 555 timer and decided to test how it would handle itself if i removed the output resistor. The manual says it'll source 200mA but does not mention a minimal output resistance. I removed it and configured my amp-meter for 10A just in case things went bad....luckily

    Well let's just say that my 555 timer exploded into 2 halfs in a loud bang. Not surprisingly since the supply voltage was around 13V (within the 555's specs however).

    But nevertheless the satisfaction of seeing it explode made me wanna do it again but unfortunately i dont have an infinite supply of 555's.

    Anyone got any good stories of exploding projects ?
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Backwards capacitors make wonderful stink bombs.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Just a few months back, I accidentally connected Vcc and Vee backwards on an LM324 quad 741 opamp while not paying attention. I got about an 1.5" jet of blue flame emitting from one side of it, followed shortly by black smoke and noxious odors. :rolleyes: My large and expensive breadboard bears battle scars from this unfortunate encounter. :( This was actually the first accident I'd had with electronics for many years.

    Electrolytic caps connected backwards will either emit a loud "BANG" or simply stink when the top blows off.

    It's not much of a challenge to destroy electronic components; just run them outside their maximum ratings for a bit.

    The true challenge is to build circuits that will operate predictably and reliably for considerable periods of time, inexpensively.

    If you enjoy seeing things getting blown up, spend some time in the military. They're paid to do that type of thing.
     
  4. Audioguru

    New Member

    Dec 20, 2007
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    The lousy old LM324 is completely different to the lousy old 741.
    1) The LM324 has low supply power, the 741 has normal supply power.
    2) The LM324 works at a supply voltage as low as 3V. The 741 is spec'd only at 30V but some work with a supply of 10V.
    3) The input of the LM324 works at its negative supply voltage that could be 0V. The inputs of a 741 fail if they are closer than 3V from its negative supply voltage.
    4) The lM324 has ouputs that can go down to its negative supply voltage that might be 0V. The output of a 741 goes down to plus 1.2V above its negative supply voltage.
    5) The LM324 has 3% crossover distortion (because its outputs are not biased properly because they have low supply power). The 741 has low crossover distortion.
    7) The LM324 has a bandwidth of only 6kHz at half its max output voltage swing. its bandwith is only about 1kHz at its max signal voltage swing.The 741 has a bandwidth of 9kHz at max output swing.
    8) The LM324 has PNP input transistors that need a source that sinks current. The 741 has NPN input transistors that need a source that sources current.

    Because they are both old, they have high noise.
     
  5. inventorjack

    Member

    Apr 4, 2009
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    My electronics must be boring. I usually just get smoke.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    I just posted that so I could see you rant. ;)
    Worked like a charm. :D
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Keyboard can be fun.
     
  8. mxabeles

    Active Member

    Apr 25, 2009
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    I blew up 7805 regulator and saw a glowing orb of orange in my 555 timer prefiguring a loud pop all in the span of an hour.
     
  9. thingmaker3

    Retired Moderator

    May 16, 2005
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    Are we overheating components or neophilic Ontarians?:D

    I really don't like it when I have something blow. It means I screwed up.
     
  10. Wendy

    Moderator

    Mar 24, 2008
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    Amen to that! You want to see something interesting, try watching the chip die themselves when they burn out, as in microelectronics. I've see the red heat of a diode die spreading throughout the die, until it hit the gold wire bonded to it, and melted.

    Then there was the TTL chip that had a common error on one substrate. The chip looked like a little city at night, with all it's junctions glowing with a soft white light (this was in the 70's). Of course, it was zapped at this point. I'd turn off the microscope light and admire it for a few minutes, before I wrote it up to have it replaced, and the wires put in the correct places.
     
  11. leftyretro

    Active Member

    Nov 25, 2008
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    Well there was that one time I was going to be extra safe and discharge the filter caps on a 350vdc power supply by shorting out the filter caps screw terminals with my 8 inch flat blade screwdriver. The fact that in my rush to be extra safe I forgot to turn off and unplug the power supply caused it to turn my nice flat blade into a ice pick. Big bang, big sparks, and smelly underware. :cool:

    Lefty
     
  12. Wendy

    Moderator

    Mar 24, 2008
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    Presevere and screw up, you too will fail spectacularly.
     
  13. inventorjack

    Member

    Apr 4, 2009
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    Well, obviously you're not doing it right.

    ;):D
     
  14. loosewire

    AAC Fanatic!

    Apr 25, 2008
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    When you loose an eye, no more play time, you can get a job for being
    disabled. AN ADVANAGE over a serious tech.
     
  15. flat5

    Active Member

    Nov 13, 2008
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    Not blowing anything except maybe the circuit breaker but I used to enjoy making arc gaps from the carbon rods of D batteries (bucket of salt water for series resistance) when I was a kid. Melts concrete real good :)
     
  16. Peace Frog

    Member

    Apr 13, 2009
    18
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    The first encounter I've ever had was when I was 6 and decided to run 18 volts through an LED. The top blew off and hit me in the face.

    More recently I was building a multiple voltage DC power supply (3.3, 5, 9) and I was using a single-piece bridge rectifier. I don't know what happened but it simply started boiling solder out from the bottom.

    Ohh, I've also reverse-biased a diode with a high current supply accidently hooking up a solenoid backwards. That was fun.
     
  17. lespaul

    Active Member

    Jan 30, 2008
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    My Favorite are Tantalum's soldered in backwards. depending on the manufacturer you either get a nice blue flame or a loud pop. We had some bad silkscreen on about 25 circuit boards and when they were all powered up....they popped all at once.
     
  18. Wendy

    Moderator

    Mar 24, 2008
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    I remember working on a test fixture that had a severe noise problem. I was using cool spray at the time. The tantalum we used at that time had a bad habit of failing prematurely, sometimes catching fire, which is what happened here. They burn just like matchheads, I used that same can of cold spray as a fire extinguisher, since I would have to repair whatever this flame damaged.
     
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