Alternative Astable Multivibrator with 50% Duty Cycle:
In yet another scheme, the diode is ignored altogether and still one may obtained 50% duty cycle.
Figure: Alternative Astable Multivibrator with 50% Duty Cycle
As with the earlier circuit, while V03 is high, pin 7 is open and the charging of the capacitor takes place through RAC therefore, TH remains TH = RA C ln 2.
For the duration for which V03 being Low and pin 7 acting as a short, the time TL may be calculated as follows. The discharge equivalent circuit may be made as follows :
Figure: Equivalent Circuit for the Case when Pin 7 Acts as a Short
Before the situation represent in the equivalent circuit arises, the following apply :
at t = 0, V c (0) = (2/3) V cc