This circuit that appears in several versions in this section and on this website was found in documentation from the 1980s. The transistors can be of any general purpose NPN type like the BC548.
This version of an astable CMOS with the 4069, and which appears elsewhere on this site and in...
Found in na 1970 EDN this circuit has a parallel regulation providing a symmetrical output of 15 V....
This circuit is the receiver for the previous remote-control transmitter. We found it in the same...