This circuit was found in a Popular Electronics from the 90's. The operating curve is given next to the diagram. The power transistor must have a heat sink.
The 747 is an old operational amplifier. This configuration suggested in the component manual is...
Suggested by Siliconix in 1980s documentation, this circuit uses currently uncommon components. The...
In the figure we have a circuit to excite a piezoelectric capsule taking advantage of its resonant...