We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the time and the diodes in the dotted board must be mounted on the output transistor heatsinks.
This circuit was obtained in a manual of the used old operational amplifier. However, the same...
This circuit is from a 1992 publication, but can be mounted very easily today. The circuit is...
Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine....