Power supply for secondary elements in main circuit?

[d4n13l]

Hello, I'm new to electronics currently working on building a power supply. My plan is going from a simple unregulated one

and then build on it until I understand how all parts work, and so get to something like this one

1. My problem now is that I want to add digital voltage and amp meters and also I'll need a fan for the heatsink that goes with the 2n3055, but I'm not sure if I should add an independent power supply that provide power for them independent from the rest of the circuit or draw power directly from the main circuit.

2. The fan I have requires 12v while the meters need 5v which in the spirit of learning, I'm thinking of building a linear voltage regulator for them, but for what I understand they are not very efficient, any suggestion how would be better to approach this?

[rdl]

You will probably need an auxiliary supply for the metering, with many digital meters it is actually a requirement. If you are intending to build a linear power supply such as those in the schematics attached, inefficiency in a small auxiliary supply will not be too significant. A fan could just be run directly from the transformer secondary, unless you plan some kind of speed control. Personally, I would add more convection cooled output capacity before I would use a fan just because it would mean less noise, both audible and possibly electrical.