The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. The maximum power is 7 W with a 8 ohms load and the power can be between 9 and 14 V.
We found this circuit in the November 1992 Radio Electronics magazine. It works with both...
This circuit came out in a Popular Electronics from December 1995. It is a Wien bridge...
The transistors of this filter found in a 1993 publication can be BF245 or MPF102. The filter...