Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
We found this circuit in an old publication. The circuit can be implemented with modern equivalent...
Suggested by Fairchild in a 1980s publication, this multiplier uses operational amplifiers from that...
This low-pass circuit was found in the December 1990 issue of Radio Electronics magazine. The...