Monostable Multivibrators Summary
Then to summarize, the Monostable Multivibrator circuit has only ONE stable state making it a “one-shot” pulse generator. When triggered by a short external trigger pulse either positive or negative.
Once triggered the monostable changes state and remains in this second state for an amount of time determined by the preset time period of the RC feedback timing components used. One this time period has passed the monostable automatically returns itself back to its original low state awaiting a second trigger pulse.
Monostable multivibrators can therefore be considered as triggered pulse generators and are generally used to produce a time delay within a circuit as the frequency of the output signal is the same as that for the trigger pulse input the only difference being the pulse width.
One main disadvantage of “monostable multivibrators” is that the time between the application of the next trigger pulse has to be greater than the preset RC time constant of the circuit to allow the capacitor time to charge and discharge.