how could i get a cathode ray tube to produce a vast spray of electrons rather than a clean beam?12AX7 - 6-9-2005 at 08:34
So the whole screen lights up without a raster? Tweaking the focus grid voltages should do it.
TimLambda - 6-9-2005 at 09:23
Saps, at the back of your TV-image tube, you will see a conical wound Coil. If you remove this, then there will be no magnetic field to divert the
electron beam. If you then go to the focussing Potmeter, and move it left or right, then you will be able to make this light spot in the middle of
your TV screen bigger or smaller. By applying different voltages to (often but, don't take it for granted) the central output wire (thick
isolation because of high voltage) of this Potmeter, you will be able to make this electron beam more out of focus. By changing the ratio of the
Resistors that feeds this Potmeter (keep to total value the same), you will be able to diffuse this electron beam into a big, but less bright spot on
your TV screen.
CAUTION: A color TV operates in excess of 25 kV, and the electron cannon on the back of the TV-tube can have thousands of volts. YOU DO NOT HAVE TO
TOUCH A LIVE WIRE FOR A DEADLY SPARK TO HIT YOU, IT WILL JUMP AND BITE YOU FROM A CONSIDERABLE DISTANCE.
If you do not know the basics of a color TV, then please let it be. It is better to gain knowledge about electronics at a safe and harmless voltage
(and power output) before messing around with these kind of DEADLY DANGEROUS appliances.
[Edited on 6-9-2005 by Lambda]moose sniffer - 6-9-2005 at 10:19
since were on the subject: i know that crts are usually used to spray electrons on screens but is there anyway to get electrons to phosphor. and can
phosphor be activated by heat?12AX7 - 6-9-2005 at 12:12
Quote:
Originally posted by moose sniffer
since were on the subject: i know that crts are usually used to spray electrons on screens but is there anyway to get electrons to phosphor.
Say that again?
Quote:
and can phosphor be activated by heat?
Not really, but any other radiation works. My oscilloscope screen glows slightly after turning off the room lights. Stronger wavelengths (UV, x-ray)
would excite it better, depending on if phosphor interacts with it of course.
Tim
[Edited on 9-6-2005 by 12AX7]Twospoons - 6-9-2005 at 23:24
Quote:
Originally posted by moose sniffer
: i know that crts are usually used to spray electrons on screens but is there anyway to get electrons to phosphor.
Its called electroluminescence. It involves direct injection of electrons into the phoshor via several intermediate compounds. Its the process used
in OLEDs.
