Newbie electronics "tinkerer" here. Soldered a circuit I'm not certain works. Did some tests I saw on youtube and all seems fine.

So, anyway.... Soldering the circuit my (tantalum) capacitor (4.7uf/25v) got slightly burnt. I'm just wondering how much heat stress a capacitor can take before not functioning?

Also, feel free to recount tales of exploded circuits related to soldering incorrectly.

 

Are you sure that it has burned, not just that it has a bit of burned flux on it?
Since we stopped using germanium transistors, most things will take a remarkable amount of abuse without failing, provided that you remembered to switch the power off first.*
These days, connectors are the most easily damaged, followed by surface-mount MLCC capacitors (the ends fall off).

*The only thing worse than forgetting to turn the power off before soldering, is forgetting to turn the power off before giving the board a good wire-brushing.

 

One awesome feature of tantalum caps is that they will work ok if the polarity reversed.....for a while which may be minutes to years. But at some point they will explode, releasing a nasty cloud of purple smoke. It's my understanding you'll never forget the smell after it happens once.

 

One awesome feature of tantalum caps is that they will work ok if the polarity reversed.....for a while which may be minutes to years. But at some point they will explode, releasing a nasty cloud of purple smoke. It's my understanding you'll never forget the smell after it happens once.

Yes - it's really foul.
They can also explode when forward biassed, for no particular reason.
Tantalum capacitors are worth avoiding, if for no better reason that there is an awful lot more aluminium on this planet than there is tantalum.

 

Yes - it's really foul.
They can also explode when forward biassed, for no particular reason.
Tantalum capacitors are worth avoiding, if for no better reason that there is an awful lot more aluminium on this planet than there is tantalum.

The company I used to work at had a data collector that had been used for more than 5 years come back for repairs after a bang. There was enough of the exploded cap left to see that it had been installed backwards. Very strange that it could work that long before exploding.

 

The company I used to work at had a data collector that had been used for more than 5 years come back for repairs after a bang. There was enough of the exploded cap left to see that it had been installed backwards. Very strange that it could work that long before exploding.

I used some once, that had the positive terminal marked by a black line (the sort of line that looks like a minus sign), and then another batch where the said line was placed almost equidistant from the two leads.
After that, I stopped using them, switched back to good old aluminium electrolytics suffered no problems as a result, and saved money.

 

I'm just wondering how much heat stress a capacitor can take before not functioning?

If you're referring to heat from soldering, 5 seconds at 260C is typical. Datasheet from Jameco attached.

I've melted LED encapsulation (T1 package) by applying too much heat while soldering.