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.

2 kommentarer:

  1. I stumbled upon your blog site while I was looking for some example code to work with a Nordic RF module along with .Net Gadgeteer. I just want to say that I am very impressed with some the article you have written in the past year and half. Thank you for sharing your knowledge with the rest of the world. Good job, and please keep writing.

  2. Hello Harish,

    thanks for the encouraging words! As a developer - and electronics tinkerer - I'm every day searching through forums and other people's blogs to find solutions to some of the technical problems I face, and as such I thought it important that I try and repay that, somehow. Very glad to learn it was useful to you. Do you have a blog yourself? I encourage you to start one if not; even posting just three-four times a year about the tiniest thing may be just what some poor guy needs to get his project going. Good luck to you.