....
3. Radar emissions can sometimes be tested by carrying a light bulb into the field and observing as it lights up. This denotes a signal strength that is above recommended levels. By then, it is probably too late. Some brain cells are dead even if you survive. At one time, it was believed that this was a 'safe' level.....
PE
Depends on what you mean by "light bulb".
In olden days, ham radio operators would "test" radiating patterns of various antennas by waving a flourescent light bulb (really a tube) along the antenna wire. It was the RF energizing the florescence that lit the tube.
This would not work with an incandescent bulb which uses a filament.
In olden days, ham radio operators would "test" radiating patterns of various antennas by waving a flourescent light bulb (really a tube) along the antenna wire. It was the RF energizing the florescence that lit the tube.
This would not work with an incandescent bulb which uses a filament.
I agree fully with most of what you are saying.
Consider this though. A light bulb is a tungsten metal filament in an inert atmosphere, and a flash bulb is a magnesium metal filament with an oxidant present.
Electrically generated heat causes both filaments to glow, but the flashbulb ignites due to the oxidant and the light bulb does not, it just glows.
If there is enough electrically induced current to fire a flash bulb (about 3 V or 2 D batteries in old style holders) then a 1.5 v or 3 v tungsten lamp would also be expectd to glow in the presence of a similar induction field. And, tungsten is a better element for that than magnesium.
This is what I once saw demonstrated.
In fact, there is a small test device for microwave ovens that relies on a small LED with an inductor embedded in plastic. You move it around the microwave on the outside, and if there is a leak, the LED lights up due to the induced current. Same thing with a tungsten bulb if there is enough current flowing. The lower the voltage rating on the bulb, the brigher the glow from a given microwave current IIRC.
Consider this though. A light bulb is a tungsten metal filament in an inert atmosphere, and a flash bulb is a magnesium metal filament with an oxidant present.
Electrically generated heat causes both filaments to glow, but the flashbulb ignites due to the oxidant and the light bulb does not, it just glows.
If there is enough electrically induced current to fire a flash bulb (about 3 V or 2 D batteries in old style holders) then a 1.5 v or 3 v tungsten lamp would also be expectd to glow in the presence of a similar induction field. And, tungsten is a better element for that than magnesium.
This is what I once saw demonstrated.
In fact, there is a small test device for microwave ovens that relies on a small LED with an inductor embedded in plastic. You move it around the microwave on the outside, and if there is a leak, the LED lights up due to the induced current. Same thing with a tungsten bulb if there is enough current flowing. The lower the voltage rating on the bulb, the brigher the glow from a given microwave current IIRC.
Just some thoughts for you to ponder.
PE
PE,
As you noted, a flash bulb requires the electrical potential of about 3V in order to fire. The magnesium fliament has a very low resistance (versus tungsten in an "ordinary" incadescent bulb).
The electrical potential that might leak from a microwave or be present in a jet fighter's radar device would be in microvolts at even very close distances - so the potential would be insufficient to "fire" a flash bulb.
Then, consider the OP's query which was about X-rays in a TSA airport scanner. The electrical potential of such rays would not even reach the level of radar. At the end of the day, returning to the OP, I don't think that the airport x-ray is going to fire his flashbulbs. I think most of the initial responses were "tongue in cheek" and then.....
I am just not sure about today's focused high energy x-ray devices in airports. After all, there are reports of film fogging that are more and more common. I'm also sure that the resistance of a tungsten bulb is rather low. In fact, a 60W bulb measures about 15 ohms with my VOM. I couldn't find a flash bulb, but I have some. They are packed away somewhere waiting for the time when I need them though.
So, I really don't know what modern X-ray will do to a flash bulb, and that is my point and it has been all along! We can't say "No it won't" or "Yes it will" categorically with 100% assurance.
PE
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OK, I'm certain I won't use flashbulbs in the microwave.
THis is really interesting, and the only way I can think of finding out if the machines will kick off a flashbulb is to try it. Wouldn't think of packing it in baggage, gotta be carry-on.
Really time to ask TSA... and - of course - a TSA inspector can reject something not officially excluded... so, maybe foil filled flashlamps would be pretty freaky to him.
But I don't know if many of us will be flying with #2 or #3 lamps.... 25s or AG1s are plenty of light.
I'd love to shoot my old barn with 8x10 and some flashbulbs,
but I would ship the lamps ... and the camera, and film, and stuff... anyway,
and never try carry-on. Probably ship the lamps in their own box, and early enough to know if they were stolen, I mean, sidetracked by the officials. Interesting stuff guys.
I did ask TSA, and got an 'ok'. As for the x-ray machine, I suspect that any field strong enough to set off a flashbulb woud seriously fry most modern unshielded electronic chips. 3 volts is a lot of power by microelectronic standards.
I did ask TSA, and got an 'ok'. As for the x-ray machine, I suspect that any field strong enough to set off a flashbulb woud seriously fry most modern unshielded electronic chips. 3 volts is a lot of power by microelectronic standards.
That is a very good point!
Do they pass computers through the x-ray or do they hand inspect?
That would give us a clue there. Although the resistors would probably tend to damp out any induced current to some extent, it could hurt a computer. OTOH, many parts are designed to withstand up to 5 volts.
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