This is the circuit diagram of DC voltage doubler / DC converter. The circuit will convert 12VDC power supply to become a 24VDC at and 18VDC. Almost any PNP or NPN power transistors should be work for this circuit.
Parts list:
- C1 and C2: 50μF/25V
- Q1: TIP 29, TIP120, 2N4922, TIP61, TIP110, or 2N4921
- Q2: TIP30, TIP125, 2N4919, TIP62, TIP115, or 2N4918
- U1: NE 555 timer