This circuit shows how to build your own 24 vdc power supply with 2 A (ampere) current. The transformer of TR1 lowering the voltage of 230V with 24V secondary voltage on a transformer.
In the photos above you can see a schematic of 24 volt dc power supply that have rectification and filtering at 32V to 34V (depends on voltage and transformer)
Part list of 24 vdc schematic diagram
TIP 122 NPN Darlington power transistor
Zener diode (BZx55C12,BZx55C13)
230v 24v Transformer