Reversing Polarity On a Television...?

[DISLEX]

I would like to first start off saying I am not really sure where I should be posting this. I hope it will be fine here. Okay, now to the fun stuff!

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A few days ago while here at work, I was told by a co-worker he heard from a cornel in the army that if one was to reverse the polarity on a television set it possibly would become a sort of camera. A TV recieves a signal and outputs it to the screen. Once the polarity is reversed it then would be sending a signal back. Now this is where it gets strange. While the polarity is reversed your screen supossidly becomes the camera lense. Now the reciver of the signal can see through your TV set.

I had never heard anything like this before and I am not sure what to think. When I think "reversing" the TV set.. Okay. Cool. Why couldn't be done. What get's me is how can a screen do the actuall "seeing"? I would think that for this to happen you would need to hook up a camera for the "eye". I then begain to think about a camera. Is not a camera mearly a tube and a lense? The same as a TV?

Somewhere in a television there is a solid state relay. (So I hear) - (this is older info, now it may very well be a chip or even digital data encoded into the chip bios with todays modern technology) The solid state reley mighy have been/be a sort of remote control to start back-feeding the signal back to the "source".

I would now like to let you all know that I am not saying I beleive this nor am I someone who really get's into government conspericies. I am just wanting to find out if any of you here have heard of this. I would also like to discuss this further in depth. I mean, if you think it will not work.. Let's talk about how we could make it work. If you do think it is true/possible.. How?

Thank you all for your time and please forgive my spelling!

[don]

If you reverse the polarity of your tv set you would in effect cancel the signal and that is that.
You could also run the risk of blowing up your telly. I can pretty much guarantee you that you
telly will not turn into a camera lense. Another urban legend that is all.
Cheers big ears!

[DISLEX]

Would you mind giving a little more detail?

[Noia]

er..it's crap...you TV has a Rectifier to turn AC power to DC power....thus, reversing it, would have no effect. YOur TV has an Electrongun on the inside that shoots electrons at three diff kinds of material (Can't remember the name), these light up. reversing the polarity, would not turn the electron gun into a reciver, because an electron gun is inshort, a bunch of wire and a metal plate....oh well....hope this helps

- Noia

[don]

Here goes more detail, think of it as taking the toal opposite of something and smashing it together with it's opposite. You would get nothing for they cancel each other out. If this does
not explain it then think of modulo two addition.

[DISLEX]

Okay I do understand what you both are saying.

Forgetting the whole screen to cam idea... Now, why couldn't the chip (or whatever) send back signals? This part is very possible I would think. ?

[Zpeef]

Because the semi-conductors (and other components) blocks the current from going the other way.

[neel]

The membrane (the flat thing you watch to and gives light in special circumstances) won't shoot fotons or electrons or whatever. It's like superman shooting laserbeams out of his eyes. I can tell you pretty sure that ain't gonna happen by switching polarity anywere in yer television. And even if you'd succeed you'd have another 1000 practical problems to overcome to record the stuff in any way.

[don]

What you are now talking about is a transceiver. Your television is a "receiver" ie: will only receive and decode signals. It will not send them out.

[Und3ertak3r]

hmmmmm .. the story is a load of BS.. reverse the polarity will certainly cancell the signals.. it will also let out all of the smoke...

Now down to fact.. The reciever in your TV or any radio frequency recieving device has an ocillator (local Osc).. this signal can and does "leak" back out of the unit sometimes into the antenna.. this signal can be recieved upto 300m (1000ft) from the set.. this generally contains no usable information... it is of use to various departments to determin what TV, Radio channels are being recieved in a given area.. hmm very interesting signal profile from radio frequency scanners.. hmm should this person be listening to the Mobile phones???
So yes Yor tv can be a transmitter.. But certainly not by reversing the polarity...
can it be used to transmit information... yes.. but various electrical modifications are required..

As for the "Chips" sending back information.. well that won't happen by reversing any polarity.. end of story.. The signal paths are set and will not reverse.. You have the signal input, and outputs.. the path can not be reversed.. As I said earlier.. only "signal leakage" is the only way out for signals in a TV..

Can you use the TV picture tube to capture pictures....Hmm I remember a Joke Powerpoint file doing the rounds a few years ago.. that purported to capture images of the operator from the computer screen.. the final frame gave the real story..


Cheers