22 Mar
2005
22 Mar
'05
3:52 p.m.
(And they are relatively expensive.) Tantalum
capacitors will fail
in a particularly spectacular fashion if reverse-biased. One day
when we arrived at work, there was a 3/4-inch hole burned through our
multi-thousand-dollar prototype PCB, and a charred spot on the
workbench below it. Although there was not enough evidence left to
prove it, we believe that a tantalum capacitor had been installed
backwards.
May not have been.... I've had tantalum capacitors 'go up' for no good
reason, they burn spectacularly give off a large cloud of smoke, and
often the remains on the boasrd is glwoing red-hot at the end.
When I say 'no good reason', I mean I've had PCBs that have been used for
say 5 years, then stuck on the shelf for a few months, then they go up a
day or so after putting the board back in service.
They certainly weren't fitted backwards.
-tony