I have a question: I connect the 220V AC directly to the LED and the 220K resistor in series, and the LED can light up normally. Does this circuit have any effect on the life of the LED? ? ?
I would like to ask how the PNP transistor works when there is no voltage applied to the base and no circuit. I am a novice and hope the experts can give me some advice.
The 60th anniversary of the transistor and the 50th anniversary of the integrated circuit, one of the greatest fundamental inventions of the last century [img]http://www.esmchina.com/ARTICLES/2005JUN/