Hi,
Modified a drawing of a constant voltage charger for a sealed
lead acid battery. Drawing shows components for 12v or 6v battery.
The charger requires a dc input, at the voltages indicated, for
6v or 12v operation, capable of supplying at least 1amp.
The fuse on the battery output is recommended, if you short out
a fully charged lead acid battery, without a fuse, you will
get a flash and a dark brown smell.
The diode D1 in series with the charger output, this is to
prevent self discharge of the battery via the resistor divider,
when the charger is not connected to a dc input source, also
protects the regulator from high reverse voltages.
It does slightly affect the stability of the constant voltage
output.
If you want to use the circuit for a bog standard bench supply,
where the dc input source is always connected, omit the diode and
the battery. This will give you a bench psu of +12v or 5v.
[set P1 pot to suit] for your project experiments.
Regards
EricG