astable multivibrator circuit as a pulse generator?

Discussion in 'General Electronics Chat' started by pyruvicactionpotential, Dec 12, 2013.

  1. pyruvicactionpotential

    Thread Starter New Member

    Mar 2, 2013
    is an astable multivibrator circuit a pulse generator or does it just behave like one? Is it possible to buy one if it's too complicated to design it?
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Fleabay is full of them, including the 555 version...
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    There are several things you should know about pulses and pulse generators.

    Pulses have variable length within their period, characterised by a vairable mark to space ratio.

    Astable multivibrators have a nearly equal mark to space ratio (M/S ratio). that is they generate square waves.

    To produce a pulse generator where you can control the M/S ratio a good way is to use a contollable monostable (or one shot), fired by an astable.

    Thus the astable defines the pulse repetition frequency (PRF) and the monostable defines the length of pulse.

    A further complication is that pulses normally operate from zero volts to some positive voltage. That is they are all positive
    Square waves are often balanced about zero.
    So proper pulse generators also allow voltage conditioning to set the output voltage and perhaps its bias.