The difference between this circuit and the previous one is that it uses PNP transistors. The circuit is from Radio Electronics magazine from July 1968. The frequency depends on R1 and C1.
An stable multivibrator with 50% of duty cucle can be mounted using the 555 as shown by the...
This circuit was found in the old Mullard transistor reference manual from 1960. The circuit uses...
We found this circuit in a 1976 documentation. The transistor and the integrated circuit must have...