This step of two transistors has a high input impedance due to the use of FET. We can use BF245 for this function and the bipolar can be BC548. The circuit is from an 1975 American documentation.
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...