This interference rejection circuit for telegraphy was found in a 1980s documentation for radio amateurs. The integrated circuits used are common today.
We found this circuit in a 1960 Sylvania transistor manual. The relay can be 12 V and C1...
March 2017 - Mouser Electronics announces the availability of MAX17523, an overcurrent and...
Found in 90s Popular Electronics, this circuit uses common general-purpose transistors in a...