Description
Source http://www.bowdenshobbycircuits.info/page9.htm#toggle4.gif
The circuit below illustrates generating a single positive pulse which
is delayed relative to the trigger input time. The circuit is similar to
the one above but employs two stages so that both the pulse width and
delay can be controlled. When the button is depressed, the output of the
first stage will move up and remain near the supply voltage until the
delay time has elapsed, which in this case is about 1 second. The second
555 stage will not respond to the rising voltage since it requires a
negative, falling voltage at pin 2, and so the second stage output
remains low and the relay remains de-energized. At the end of the delay
time, the output of the first stage returns to a low level, and the
falling voltage causes the second stage to begin it's output cycle which
is also about 1 second as shown. This same circuit can be built using
the dual 555 timer which is a 556, however the pin numbers will be
different.
Circuit diagram Source http://www.bowdenshobbycircuits.info/page9.htm#toggle4.gif
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