Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms. The circuit can be built with modern equivalent transistors.
We found this circuit in a European publication from the 1970s. The transistor is made of...
This circuit uses a current regulator from the 90's. This component is uncommon nowadays. The...
Powering from a 36 V supply this circuit has a power output of 16 W in 4 ohm loads. With 40 V and...