This hobby circuit below will generate a 24v DC supply with just a bit of
ripple voltage. It is rated at 2 Amps.
This hobby circuit works by opening and closing a switch routing DC
pulses into the energy storage capacitor C2. The transistor Q2 is turned on when
the voltage from the bridge rectifier is below 26v. This allows C2 to charge up to
about 25 volts. As the bridge voltage increases, the transistor Q1 then starts
turning on, which in turn turns off Q2. The result is a voltage across C2 which is
pumped up to about 25 volts and is discharged to about 23 volts before the next cycle.
The average voltage is pretty close to 24 volts.