We found this circuit in a 1980s publication on telephony. The circuit uses an integrated amplifier from that time, which is uncommon today.
This amplifier was found in a 1957 Rayrtheon documentation. The circuit can be fitted with a BC558...
This circuit was obtained from the May 1971 issue of Radio Electronics magazine and is intended for...
Although it is a common configuration today, this circuit was taken from an old publication. The...