To obtain a "Delay On" the most frequent recommendation is to use a PNP transistor. Easy. But if controlling a higher voltage circuit, the 555 does not cannot raise the base of the PNP transistor high enough to turn it off.
Looking for solutions, the simplest I've discovered is here: http://clarkson-uk.com/555-timer/operation/frames3.html.
It works perfectly on a breadboard.
What I don't understand, though, is what is the purpose of the diode ?
Hoping for help (and understanding),
Mike Hains
Looking for solutions, the simplest I've discovered is here: http://clarkson-uk.com/555-timer/operation/frames3.html.
It works perfectly on a breadboard.
What I don't understand, though, is what is the purpose of the diode ?
Hoping for help (and understanding),
Mike Hains
