This is 5v 12v dual power supply circuit using 2N3055 and Zener diode for 12V then to LM309 or IC-7805 dc regulator IC for 5V output which easy circuit [...]
Though very ancient, it still is many useful.
You want to use a DC regulator or learn about voltage regulators using 2N3055. Why use this transistor? Normally, it can be used with loads that require a current not…
Good transistor audio amplifier circuit, at 40 watts OCL RMS using 2N3055+MJ2955 is easy to build,and very inexpensive. To use Power Supply +35V -35V 2A.