The truth about electronics and smoke

Regardless of Dave Barry's insightful article on electricity. I must set the record straight.

*** All electronics run on "smoke", not electricity. ***

I have worked in electronics for almost 40 years. In that time my experience has ranged through radar systems, tape and disk data storage, data processing, telephone switch systems, power conversion and power inverters for solar PV. In all of this, there is one common thread: smoke.

What I mean is, all electronic systems run on smoke! Prove to yourself, if you let the smoke out of any electronic device, it will promptly cease functioning as intended by the designers. Therefore, it is imperative, the smoke must retained within these components!

Early on, while working around US Navy equipment, I would sometimes hear someone comment "It's time for the SMOKE TEST." This announcement usually followed extensive maintenance or repair; when it was time to turn on the MAIN POWER switch. It really was not possible to do this gradually, so someone would get their nerve up, cross their fingers, and simply flip the switch. Everyone in the area was responsible for monitoring emissions of smoke. If none was observed for a reasonable period of time then we would assume the smoke was not going to be released and everything would be okay.

If we found a piece of equipment with all of it's smoke removed, it was considered beyond repair, and out at sea, we gave it a float test (sorry Dave Letterman, we were first).

Sometimes electronic components would out gas their smoke along with explosive sounds, flashing light and occasionally fire. I consider these effects simply as a user alert to the problem of the loss of smoke.

For example, I sometime hear people jokingly refer to a Sound Emitting Diode (SED). In reality, this is a Smoke Emitting Diode. And once any smoke has escaped the diode, it will no longer function.

You might counter this by saying, "I've seen plenty of electronics stop working and there was no smoke." Rest assured, there WAS smoke. It may have been a very small quantity (in the case of sensitive devices), or it may have dissipated before you noticed. Hence the need for sound emissions or light emissions to accompany the smoke.

However, not all electronic systems failures are related to smoke. This can be a result of software bugs. On occasion these bugs get into the equipment and play havoc. It is a historical fact, the first computer bug caught interfering with normal function of electronics was captured on Sept. 9, 1947 and taped in a lab notebook. Now on display at Naval Surface Warfare Center Computer Museum at Dahlgren, Virginia (http://www.history.navy.mil/photos/images/h96000/h96566k.jpg).