William Sommerwerck wrote:

polygonum wrote

William Sommerwerck wrote:

One might argue that all the transistors are created simultaneously in a
single processing sequence, and that the chip is, technically, a single
component.

One might argue that is the case for the 100-component circuit referred to
in the EE Times article.

One //might not// argue that. The LED lamp is made of discrete components that
are manufactured separately, and individually soldered in place.

The original article makes the very crude leap from one filament with a
claimed 0.0001% probability of failure (shouldn't that approach 100%
after a thousand hours?), to 60 electronic components yet assumes they
each have the same 0.0001% probability of failure, multiplying them up
to give a 60x higher failure rate for the LED vs the incandescent.

Subject to my eyesight, in the circuit chosen there appear to be 1
integrated circuit, 8 diodes, 8 transistors, 11 capacitors, 26
resistors, 2 chokes, 1 fuse.

Each of these classes of component have different probabilities of
failure, and in "cheap" PSU circuits it tends to be the capacitors with
the highest, for a given circuit a bit of analysis will probably reveal
three or four "pinch" components that are likely to be responsible for
90% of all the failures.

Searching for other LED lamp schematics, was that one chosen because it
was considered a well designed circuit, or because it has a conveniently
high component count?