To: i_dont_chat
How many people are nostalgic for watching the tv picture tube turn completely OFF as the picture shrank down to dot before fading out?
21 posted on
05/30/2008 10:53:25 AM PDT by
weegee
(VOTE MCCAIN: Susan Saradon says she will move to Italy or Canada if he's elected)
To: weegee
That was a cool effect. I learned later that it was due to the sweep circuits for horizontal and vertical deflection turning off more quickly than the electron gun in the picture tube. The sawtooth wave was generated by vacuum tubes and as soon as the “grid” voltage dropped below a critical level the tubes would shut off. The lack of sweep would cause a brief centering of the beam, and that coupled with the persistence of the phosphors would result in the slowly-fading central “dot”.
29 posted on
05/30/2008 11:03:48 AM PDT by
chimera
To: weegee
How many people are nostalgic for watching the tv picture tube turn completely OFF as the picture shrank down to dot before fading out? That, and in the old days when stations went "off the air" at 1AM or 2AM, and after the national anthem and/or a hymn, there would be a black screen for a few seconds, then an abrupt transition to snow.
The loneliest feeling in the world, to one experiencing it for the first time...
Cheers!
75 posted on
05/30/2008 6:22:15 PM PDT by
grey_whiskers
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