Motorola suggests this circuit in an 80's documentation. The circuit uses an inverter to produce a higher voltage for 9 V battery charge from a single cell.
This circuit is from an Electronics Now from August 1995. The triac is according to the load that...
The figure shows an application of the LM377 in a small inverting stereo amplifier with output...
Found in an American 80's documentation, this circuit can use common FETs like the BF245 and cover...