WHICH is better use two output transformer or use the regula

[sherazi]

i want to design a pcb bsed pwr supply... what would be economical as well as good in circuit...
a) use a transformer with outputs for 12 and 24 volts?
b) use a 24 vlt transfrmer and use a 12v regulator to get 12 v frm it?

 

[farhada]

It depends of what you mean by better? If you are OK with loosing a lot or power, but have a cheaper transformer, then go for a single 24V solution, or if it is more important for you to save energy but a bit more expensive design, then chose the second option.

 

[sherazi]

ok which transformer can i use for 12+24 output having 230v at primary... can u give me part number too... i hav to mount it on pcb

 

[betwixt]

Re: WHICH is better use two output transformer or use the re

As Farhada states, it depends on what you need the power supply to do.

The simplest method, if half-wave rectification is adequate, is to use a 12-0-12 transformer. Use one of the '12' as ground, take 12V from the center tap ('0') and 24V from the other end.

Try Farnell for transformers. www.farnell.com

Brian.

 

[sherazi]

Re: WHICH is better use two output transformer or use the re

i am posting this sch... dont consider the transformer as i couldnt get the center taped in the library and was in hurry... is this correct way... having 24v trfmr ... is it ok

 

[sherazi]

Re: WHICH is better use two output transformer or use the re

As Farhada states, it depends on what you need the power supply to do.

The simplest method, if half-wave rectification is adequate, is to use a 12-0-12 transformer. Use one of the '12' as ground, take 12V from the center tap ('0') and 24V from the other end.

Try Farnell for transformers. www.farnell.com

Brian.

would they be cheaper and of good quality... i have to focus on both... or can i have them from china

 

[betwixt]

Re: WHICH is better use two output transformer or use the re

Your schematic is not correct.

I said if you use half wave rectification you could use the center tap trick. You join the two secondaries in the middle. Call them secondary 'A' and secondary 'B'. Ground one side of A, this becomes your negative line. Join the other side of A to the near side of B, connect the junction to a single diode to produce your 12V line. Take the top end of B through another single diode to produce your 24V line.

It isn't ideal but it should work.

Farnell export to Oman so you should be able to buy from them. Chinese transformers MAY work but they don't have a good reputation!

Brian.

 

[farhada]

Take a look at this page for basic design of different rectifiers:
https://www.allaboutcircuits.com/vol_3/chpt_3/4.html