This circuit is used in frequency meters to isolate the input output. The circuit is from old documentation. Equivalent operational amplifiers can be used.
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...