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Name: Unknown
Status: student
Age: 30s
Location: N/A
Country: N/A
Date: 11/15/2004


Question:
What happens to the electrons that bombard the screen of a television when it is switched on? They cannot just disappear. Only when the television is turned off and on does the electrons stick to the outside of the screen. Also, when I switch off my computer screen electric discharge sounds are heard at the back of the electron gun. Please comment.


Replies:
You are right in that electrons do not disappear. They move along the back of the screen through the power supply that is keeping the inside of the screen at a very large positive voltage (perhaps 25,000 volts) so the electrons are accelerated toward the screen to cause the correct phosphors to glow when they strike it. I do not know why there are electric discharges at the back of the electron gun when your computer is turned off; perhaps it continues to be charged up with electrons, but the electrons are not accelerated towards the screen since that voltage may already have fallen to zero. This could make the gun very negative and the resulting discharges are the electrons escaping.

Best, Dick Plano...



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