Power Supply Design

[darkatsuki12]

I would like to make a Power Supply with a specification of:
Variable (0-25 V DC)
w/ Course and Fine Adjustment
3A Max
w/ short Circuit protection(auto shut-off/current limiting)
Use Discrete Components

I'm quite a Newbie so I don't really even know where to start. Can you tell me a step by step procedure of how to make the circuit diagram, reasons behind its process and some points I need to consider while designing the Power Supply and share your circuit diagram.
Thanks.

 

[dr pepper]

Any reason why you want to use discretes, ic's will make the supply better simpler to build then a pure transistor design.
The LM723 still seems popular for enthusiats, allthough it is a dated chip.

 

[darkatsuki12]

Any reason why you want to use discretes, ic's will make the supply better simpler to build then a pure transistor design.
The LM723 still seems popular for enthusiats, allthough it is a dated chip.

My teacher demands me to use only discrete components.

 

[ronv]

Start with making sure of the specifications and how much money you want to spend.
For example there are parts available that make it pretty easy to go as low as 1.25 volts, but going to zero is more difficult.
Do you need 3 amps, or would 2 be enough. Same with voltage. Would 15 or 18 volts be high enough?

 

[ladyphoebe15]

Start with making sure of the specifications and how much money you want to spend.
For example there are parts available that make it pretty easy to go as low as 1.25 volts, but going to zero is more difficult.
Do you need 3 amps, or would 2 be enough. Same with voltage. Would 15 or 18 volts be high enough?

Isn't this the specification he needed:
Variable (0-25 V DC)
w/ Course and Fine Adjustment
3A Max
w/ short Circuit protection(auto shut-off/current limiting)
Use Discrete Components

 

[alec_t]

Is this just a design exercise or are you required to build a working power supply?
Clearly you will need 'feedback' to control current and voltage. Are you familiar with that concept?
Are you able to design a simple transistor amplifier stage for providing the feedback?

 

[darkatsuki12]

Is this just a design exercise or are you required to build a working power supply?
Clearly you will need 'feedback' to control current and voltage. Are you familiar with that concept?
Are you able to design a simple transistor amplifier stage for providing the feedback?

I am required to build it and sadly, i don't know that concept.

 

[dr pepper]

Your question sounds more like a homework question.
Have a look at this, but dont just build it like a lot of students do these days at least make an effort to understand the circuit.
http://electronicsproject.org/rippl...able-output-voltage-and-current-power-supply/
You might find T1 tricky to get on that circuit.
Heres a technical description of a similar circuit:
http://www.circuitstoday.com/contro...or-with-overload-and-short-circuit-protection

 

[alec_t]

This may help you to understand how feedback is used to regulate voltage:
http://www.ko4bb.com/e102/e102-5.php