Help: Regulated Power Supply

[hardcore misery]

we were asked by our professor to design a regulated power supply which

the input voltage is 220V to 9v( increment of 3v... example, 12v, 15v, 18v and so on individually, we will choose a specific output voltage)

we were told to do not use an IC and include all computations how we arrived from choosing the desired components..

could someone here can give me some links to sample schematics w/ computations or any site that can help me through these...

big thanks to all you zires...

 

[Phasor]

Were you given any other parameters for the PSU? % regulation? Output current?

One of the most basic regulated PSUs can be found here:
**broken link removed**

Change the value of the zener diode to change the output voltage.

 

[k7elp60]

The attached schematic is of a regulated power supply. If you plug in the values of the 10K resistors you will see that the output is exactly double the
value of the zener diode. If you change the values of the 10K resistors you and change the output voltage. By the same token if you change the value of the regulated voltage on the non inverting input to the op amp then you can also change the output voltage. These hints may help you with your design.

 

[Papabravo]

Aaanhhh! The OP said that he needs a design without using an IC. Question does that mean specifically a voltage regulator IC or does that requirement apply to an operational amplifier as well.

I suppose he could use one of the very old Philbrick Vacuum Tube Operational Amplifiers to meet the requirement.

 

[k7elp60]

Opps sorry I misread, but I have never heard of a 9.0V zener diode. Yea most are 9.1 with tolerances and selecting one may find a 9.0 for reference.
Oh well maybe the circuit I posted will help someone else with power supplies.
Can't please everybody.

 

[FusionITR]

Replace the op amp with a diff pair.

 

[hardcore misery]

these are the parameters:

>load current is 1A

>input voltage is 220V

>linear regulated

>i have chosen 60V as output voltage
(our professor requires us to choose an output voltage starting at 9V, but we must not have the same output voltage to avoid copying from my other classmates, but i think an output of 15V can do because 60V is divisible by 15V so if i have the computation for an output of 15V i can do the computation for 60V)

>we were told not to use an IC on the designed schematic

 

[hardcore misery]

zires, do you have any idea on solving those values of capacitors and resistors used on a designed PSU?

 

[Hero999]

Do your own coursework!

 

[hardcore misery]

still hoping for help here...

 

[hardcore misery]

up

up for this

 

[Nigel Goodwin]

How will people helping you cheat help anyone?, if you can't do your simple course work you don't deserve to pass your course - you either need to put some work in and become competent, or give up and find something you CAN do!.

 

[Hero999]

60V is a silly voltage to choose becuase it's too high and can be a shock hazard. Choose something more sensible and make it below 30V.

It isn't easy to make a stable voltage regulator without at least one IC. The problem is the reference as most zenners aren't very stable you really need a propper stable band gap reference.

Anyway, just Google it:
**broken link removed**
http://www.google.com/search?num=10...=en&q=discrete+voltage+regulator+&btnG=Search

 

[hardcore misery]

i'm thinking of designing a 15V dc output...to attain a 60v dc output, i have to add 2 voltage doubler circuit on my designed PSU, is this possible?

 

[Nigel Goodwin]

i'm thinking of designing a 15V dc output...to attain a 60v dc output, i have to add 2 voltage doubler circuit on my designed PSU, is this possible?

No! - not to be any use anyway! - if you want 60V, then design your original supply accordingly.

 

[hardcore misery]

so the 60V Dc output can be produced by the transformer? depends on the turns ratio? probably a step down transformer... is it correct?

 

[hardcore misery]

**broken link removed**

can anyone check this for errors? dc output = 15v
load current = 1A
input voltage = 220/60hz

 

[audioguru]

If the transformer is 12VAC at 15VA then it will work. But the output isn't regulated, the voltage will change if the mains voltage changes and it will change when the load current changes. The output will also have about 1V of 120Hz ripple. This circuit could feed a 7809 voltage regulator IC to give a regulated 9VDC output.

 

[hardcore misery]

we were not required to use an IC to our project...

so is ti possible to step down a 220VAC into 15VDC? then by using a voltage multiplier, 15VDC can be 60VDC? that is my design... and it should be regulated...

 

[Nigel Goodwin]

we were not required to use an IC to our project...

so is ti possible to step down a 220VAC into 15VDC? then by using a voltage multiplier, 15VDC can be 60VDC? that is my design... and it should be regulated...

In theory, but it's not generally a practical solution - forget about voltage multipliers, they are a waste of time!.