onsdag den 3. april 2013
Having an astable trigger a monostable
I wanted to have an astable pulse trigger a monostable, using the 555 timer. The main issue here is in that the trigger-pulse that's sent to the monostable 555 can't be longer than the output pulse, unless you add a 'trigger guard' of sorts.
The below schematic does the trick:
The 555 on the left is the astable, it pulses every approx 4-5 seconds. Its output is sent to the input of the 555 to the right, the monostable, which pulses for a significantly lower duration as opposed to its input pulse.
This could be used for an egg-timer, for example, where a variable resistor sounds a buzzer at a selected interval.