Astable and Monostable Multivibrators

Multivibrators is two state devices which is used extensively in digital electronics. The bistable multivibrators or called filp-flop are the basic memory devices used in sequential logic. Beside bistable multivibrator, there are also astable multivibrator which serves as an oscillator and the monostable multivibrator (on shot multivibrator) which can serve as a pulse source. The NAND gate inverters configuration shown below is one of many ways to create an astable multivibrator : a two state device which is not stable in either state.

Astable and Monostable Multivibrators circuit schematic diagram

A time characteristic of the time constant RC will reach the threshold for switching A low and B high if we start with point A high, then that high voltage charges the capacitor. Until the transition back to the original state occurs , the charging process will reverse. We can build this circuit using half of an IC7400 quad NAND gate.

If the upper part depicted an astable multivibrator circuit, the lower part is a monostable one. The monostable multivibrator or one-shot will produce a single output pulse of length t determined by the value of the resistor and capacitor in response to a positive trigger pulse. The non-retriggerable one-shot will not respond to further trigger pulses which happen during its pulse length. [Circuit’s schematic diagram source: C.R. Nave, Hyper Physics]

This entry was posted in Control Electronics, Oscillators and tagged , . Bookmark the permalink.,
Possibly Related to "Astable and Monostable Multivibrators" Circuits

  • Starting Network for Astable Multivibrator
    A flip-flop that generates two unstable states (high-low) is called astable multivibrator, a fancy name for you to say it’s an oscillator. The very basic of such circuit consist of two transistor where the collector of each transistor is wired … Continue reading →...
  • LM139 One Shot Multivibrator/Timer
    One shot multivibrator circuit is also known as monostable multivibrator or timer. The function of such circuit is simply produce a pulse strobe with a fixed width, regardless of the pulse width of the triggering input.  Below is the circuit’s … Continue reading →...
  • LM139 One-Shot Multivibrator
    The circuit below is a one-shot multivibrator. One shot multivibrator is also known as monostable multivibrator, or timer. The main function of such circuit is producing a fixed width pulse. The width of this pulse is determined by the component … Continue reading →...
  • One-Shot Multivibrator
    A one shot multivibrator generate a fixed width pulse at the output when the input is triggered. This fixed width output should be consistent, regardless the width of the input trigger. One example of one shot multivibrator circuit is shown … Continue reading →...
  • Flash-Triggered Pulse Stretcher Using Classic Monostable Circuit
    This is a flash triggered (photo-driven) circuit which produce a pulse with constant predetermined wide. This circuit can be used to control any device which is required to be synchronized with optical trigger/flash light.  The pulse can be used to … Continue reading →...

Comments are closed.