Found on an 80's Radio Electronics, this circuit is designed to pass the 300 to 34,000 Hz voice range using standard operational amplifiers.
This linear circuit was found in a 1965 Electronic Design. The transistors are from that time....
This filter was found in the May 1989 issue of Radio Electronics magazine. The components can be...
In the figure we have the way to make the connection of voltage regulators in series to obtain a...