This circuit was obtained in the 1990 Motorola Linear Databook. The circuit uses a 139 series comparator, but other series can be used. The power source need not be symmetric.
In this charger, the charging current is basically limited by the LEDs. The transformer is a low...
This circuit is from the Analog Devices component datasheet. In it we have the way to obtain a low...
Found in a Philips documentation from the 90s, this circuit uses transistors from that time....