Letter Re: EMP Telltale


Whenever the power goes out wherever I am, the first thing I do is see if my battery-operated watch is still working. I suspect one of these times, the screen will be blank or just chaos. – Sid, too near Niagara Falls

HJL Comments: As technology advances, the gate sizes grow smaller making such electronics more susceptible, but at the same time manufacturers recognize that they are more susceptible to static electricity as well. As a result, manufacturers almost always include some basic protection in the on-board circuits. Add to that the concept that the amount of energy absorbed by these electronics is directly related to the amount of “antenna” on the circuit board and you end up with practically no idea whether your watch will survive or not. The circuits are so small that the antenna lengths are negligible (unless you happen to be plugged in charging the battery during an EMP event). It is actually anticipated that most modern cell phones will survive an EMP as long as they are not too close to ground zero and not connected to external wiring at that moment. Of course, a cell phone without the corresponding cell phone tower or the ability to recharge the battery is practically useless. I would anticipate that your watch will fall in this same category of electronics. It may be an indicator, but it is not necessarily one that you can reliably depend on.