This circuit was obtained in a documentation from the 80's. However, using TTL it is still modern, being able to be used as Shields for microcontrollers or part of digital projects.
Found in a publication for radio amateurs from the 1990s, this circuit makes it possible to...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This simple transistorized receiver with earphone was found in a Japanese publication from the...