View Full Version : Dumb electrical question

10-28-2001, 11:17 PM
First, I'll admit that electricity is, to me, as mysterious as the Holy Trinity. (More so, actually, but let's leave religion out of this.) So laugh if you must, but here's the question.

I have one of those table lamps with no switch--you know, you just touch it anywhere and it comes on, or goes to the next level of brightness, or goes off. But pretty frequently, when the lamp is off and there's no one near it, it will spontaneously flash on for just a second. Is this dangerous? Will it eventually burst into flames? Is it caused by changing atmospheric conditions? Should I stop using it? I'm an ex-firefighter, and housefires can be exciting for me, but not when it's my house. Thanks for any input.

10-28-2001, 11:55 PM
Not a dumb question it seems. I found out that it is possible that your lamp could be having trouble with Radio Frequency Interference:

RF Touch lamps are RF-operated devices that often cause, or are susceptible to, EMI problems. They have a free running oscillator that is very broad and rich in harmonic energy. This oscillator is hooked up to a touch plate that changes the frequency of the oscillator when a hand is placed near the plate. Unfortunately, this plate also acts as an antenna, radiating some of the energy of the oscillator, or picking up nearby radio signals. When the former happens, it can interfere with other services. When the latter happens, the circuitry inside the lamp reacts the same way that it would when the plate is touched -- the lamp changes states from "off" to "on".

According to that information, nearby radio transmissions can turn those lamps on and off.
The technical paper also mentions ways to identify if this is the problem, and possible solutions.

10-29-2001, 01:06 AM
Hey, thanks! I actually did a quick search before asking, but I didn't really know what to look for. Ohms and circuits are hard for me to grasp, but it sounds like it isn't dangerous, so I'll just let it go and enjoy the occasional flash.

10-29-2001, 03:20 AM
I enjoy the occasional flash! ;)


Hello? *ECHO, echo, echo*


10-29-2001, 04:42 AM
I agree it doesn't sound dangerous. Sounds like the control circuit is too sensitive, but that shouldn't cause any short circuits or things like that.

I have a lamp like that and there is a knob for adjusting the sensitivity of the control circuit. Are you sure yours doesn't?

10-29-2001, 05:35 AM
Well, I don't find any knobs, at least not where I can see without taking the base apart. If it's just an overly-sensitive control circuit, I can live with that. I'm a little too sensitive myself sometimes, and I don't seem to have a knob for that either.

Astroboy, I've been waiting all my life for that other kind of flash. Nothing so far, at least not on purpose. Oh well.

Thanks again, everyone!