This astable multivibrator was obtained from a Mullard documentation from 1960. The components depend on the used transistor and on the frequency, as shown in the table next to the diagram.
This circuit, from an old publication from the 1970s, can be made with silicon transistors like...
We find this circuit in documentation from the 1980s. The triac and diac are of conventional types...
The purpose of this circuit is to convert a short-lived pulse into a negative rectangular pulse. The...