Learn Unregulated power supply! Here an important basic. You should know. Diodes rectifier, Designing, reduce ripple, capacitors filter.
The circuit that see this is power supply 6V to 9V (Input 12V) of a calculator. That have preventing something through the circuit in. The part that perform to heal strong a picture uses the integrated circuit op-amp multi-purpose 741 numbers in the character comparator mode.
This is 38V Regulated Power supply. We use the Simple Zener diode voltage regulator as main ideas, and two transistors to increase current to the load at 1A-2A.