This circuit for audio applications was found in an English magazine from the 80's. The circuit has a pass band below 3 kHz making it ideal for telecom applications.
Figure Bellow shows how to interface CMOS circuitos with TTL using the 4049 or 4050 IC. The power...
This circuit is from a manual from the 80's and the operational one used, uncommon nowadays, can...
Based on National Semiconductor's LM4130 reference circuit, this circuit was found in Internet...