Use a CD4069 as the inverter input to the 555.I have a quick occassional 12vdc pulse from an existing circuit which this circuit should change to 5vdc and hold a bit longer so it can be logged and light warning LED. See circuit below. All tips welcome, but in particular trying to figure out which op amp (or dedicated buffer) and inverter to use on the input line, since the pulses are only 3 or 4ms. I'm worried that a 741 or similar will be too slow to act as a good buffer for such a fast pulse. Also not sure which inverter to use on the input since the 555 triggers on low rather than high.
by Duane Benson
by Aaron Carman
by Aaron Carman
by Robert Keim