This amplifier was found in a 1970s documentation. Darlington transistors can be replaced for modern equivalents of at least 80 V x 2 A, equipped with good heat sinks.
This was one of the National Semiconductor clock modules very popular in the 70s and 80s. In the...
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
EDN magazine in a 90's issue published this TTL technology debouncer flip flop circuit, in this...