The integrated circuit used in this Electronics Now amplifier is not very common today. However, this configuration can be found in commercial equipment of the time.
This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the...
Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic...
This wired intercom was found in a 1960 Sylvania transistor manual. The transformers are the type...