Uses for old TVs?

Monitors for your cctv system. Or, you could use a giant array of them as a bright dot matrix display.

On a sunny day (Tue, 23 Jun 2009 09:45:41 -0700 (PDT)) it happened Too_Many_Tools wrote in :

CRTs make for a great physics experiment. You have your own little particle accelerator, shooting electrons. you can use magnets to deflect the beam, make a big (slow) oscilloscope, play with high voltages....

All that said, glad I got rid of the Xray radiating power guzzlers with implosion danger. When digital came, I put the ... oops, there is still one in the attic... thing with the garbage. And I still have a good CRT color monitor somewhere in case the liquid crystals go on strike.

mplosion danger.

ystals

Do you have links to "Make your own particle accelerator"?

TMT

On a sunny day (Tue, 23 Jun 2009 10:13:35 -0700 (PDT)) it happened Too_Many_Tools wrote in :

particle=electron accelerator=CRT brain=absent?

e,

h i=3D

...

cr=3D

LOL.

Some of us would like to accelerate more than just electrons.

Again any links to where someone has modified a CRT to be a general purpose accelerator?

Also any thoughts as to how one might be able to use an old television for a Xray machine?

TMT

You have to let the magic vacuum out to get stuff to be accelerated in there. Stuffing it back in is difficult.

You'd do better with a non-CRT tube from a really old color TV:

e,

h i=3D

...

cr=3D

LOL.

Some of us would like to accelerate more than just electrons.

Again any links to where someone has modified a CRT to be a general purpose accelerator?

Also any thoughts as to how one might be able to use an old television for a Xray machine?

TMT

e:

cope,

with i=3D

tic...

uid cr=3D

I have the means to put the magic vacuum back in. ;

The analog tuners make great spectrum analysers. figure out the bandswitching and control inputs before dismantling the TV. Just add a ramp and a 62 or 68 or 45 mhz IF , get one with a pll and one thats analog VCO and do a tracking generator. PLL ones can often be modified to step in much smaller steps then 6 mhz, or you can sweep the first IF. If you get one from the older b-w minis or some color ones, its just a VCO with a cotrol voltage, no PLL.

Steve

ccelerator?

What, use the flyback to drive a 1B3 tube made before they required x- ray shields?

Not easy to get xrays when the faceplate is designed to adsorb them.

Steve

I don't know about unique, but I've got some cable strung around my house carrying channel 3 to a bunch of old sets from a DTV converter. I can walk around and not lose track of a TV program.

When I get a round tuit, I'm going to rig up an IR remote control repeater so I can switch channels from any room.

I have a Philips PH-61153 4x1 Automatic Video Selector and RF Modulator dispersing anything on the great room set throughout the house on Channel 4. I had to get tricky with some Channel 4 traps to get everything to pass through the central distribution amplifier ;-)

Let me know when you solve that. That's my next "need" ;-)

...Jim Thompson

I just bought up a few very, very good ones for a very few dollars. I use them for karaoke players that don't already include the display; for playing VCR and DVD disks for my profoundly autistic daughter (she uses such things regularly); and I keep a few spares for later when those go bad. We also do NOT have a single HDTV in the house. I don't watch TV or cable and haven't in 20 years, now. My wife does, but she uses a converter box only. I'm not likely to soon buy an HDTV, either. Perhaps in a decade. Not now, for sure. So my wife uses them, as well.

None of that is unique, though.

Look up words like CRT, Electron Diffraction, Frank-Hertz, and the De Broglie relation. See what you can find about those.

Jon

Hmm, do you think an electron beam is coherent enough to do something like diffraction, possibly involving the shadow mask itself? Trouble is, focus and intensity go to hell when you reduce voltage, and you need a lower voltage to get the wavelength fairly large.

Tim

Frankly, I'm not sure. You may be correct. I didn't work the numbers, just recalled some experiments many years ago. Just googling right now, here's a page that quickly came up:

I'll need to read it. But to save time, I'll post it right now and read it later.

Jon

Good idea...thanks

TMT

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Just a thought, RS485 over phone pairs that someone mentioned.

IR detector ==> 485 tx ==> over spare phone pairs ==> 485 rx ==>> IR transmitter IR detector ==> 485 tx ===^ IR detector ==> 485 tx ===^

Might need a little current limiting if there are two remotes active, or some form of collision avoidance. Maybe just listen to the 485 bus to see if its active and deny transmission.

Hmmm

Cheers

I'm not very clear on IR signaling such as in remotes. Schematics found here and yon seem to use some carrier frequency in the 40KHz+ ranges. Why can't you simply make a repeater that spews forth exactly what it receives (avoiding ass-to-mouth issues ?:-)

...Jim Thompson

Back in days of my youth and younger adulthood when electronics was a hobby and not a job, I liked to grab flyback transformers. The cores were good for winding all sorts of inductors and transformers good at the frequencies at which they and power MOSFETs and common ICs of back then were efficient at.

I made things such as a 12-volt-powered ballast for PL-13 / F13TT compact fluorescents (and it produced a high pitch audible tone).

Vertical output transformers from older TVs (from mostly-tube ones) were good for cheap, convenient flyback boost converters for up to a few kilovolts, typically operating at around 100 Hz to a few hundred Hz. It's been a couple decades since I played with those, and it's probably been almost that long that these were no longer easily trashpickable.

Nowadays, if I find a TV to trashpick, and it won't take me more than just a few minutes to get tools to it, I would look for any worthwhile capacitors and heatsinks.

Electronic lamp ballasts, switchmode LED drivers, switching current regulators, switchmode battery chargers, etc. now appear to me better-done with off-the-shelf inductors when possible, at frequencies high enough to get the size, turns count and cost of the inductor down. And I like to use those open drum core ones when I can. This results from me designing such nowadays more for people looking to make such in large quantities, as opposed to designing such things to be made by hobbyists with tight budgets.

If I see a computer in the trash, unless it looks especially good/usable (in which case I ask any coworkers or the thrift shop if they want it), I am mainly after processor heatsinks and heatsink fans. Those are good for screwing around with some of today's high power LEDs.

Then again, there are some heatsinks good for many high power LEDs available from component distributors for low enough price. It would cost me less to add a few heatsinks (or almost anything trashpickable and worthwhile) to my next order from Digi-Key, Mouser, Future or Newark then to take much time away from getting work done to trashpick stuff. And if I lose much time to play from trashpicking without losing time getting work done, what good is it taking up space with toys that I don't have time to play with?

- Don Klipstein ( snipped-for-privacy@misty.com)