2N3055 + LM317T power supply regulator 1_2V-20V & 3V-6V-9V-12V 3Amp
This is CircuitPower supplyregulator Current 3Amp Voltage output : 1.2V-20V and 3V,6V,9V,12V. Use IC LM317T and 2N3055, Easy to Bulid and normal part low cost too. detail see in circuit image.