This circuit was found in a RCA documentation from 1977. The integrated circuit is uncommon today. It is only a reference.
We found this anti-theft circuit in a 90's English publication. The circuit uses common components...
This small amplifier with a low impedance microphone that can be used for hearing aid was found in a...
This circuit was suggested by Motorola in a 1969 publication. It makes use of components of the...