Based on a 555, this 80's American documentation circuit detects the voltage of a battery and can then disconnect the charger. The transistor may be a general purpose type.
Found in ancient American documentation, this circuit uses some components from the time, such as...
A JFET is used in this circuit to maintain constant gain. The circuit is from an Electronics Now...
This very low power amplifier is designed by Amperex for hearing aids. It is based on TAA370 which is...