help on power supply circuit design

[vead]

i want design schematics digram for 12v dc regulated supply i know i need transfomer, diode, capactior and other component if input 230vac output 12vdc load 20ohms and o/p current 2amp how can i calcuate working voltage, current and rating of component

 

[papunblg]

Read This:-
Power Supplies

 

[aftab_s81]

I think you need to buy the transformer (with 12VAC output), bridge rectifier, 12V regulator (7812 with can housing is good choice, it supports upto 5A current).

Aftab,

 

[papunblg]

LM7812C (LM78xxC series) : For 5Amp supply with LM7812, it needs additional arrangement to bypass hi current.

The LM78XX series is available in an aluminum TO-3 package
which will allow over 1.0A load current if adequate heat
sinking is provided. See data sheet: http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS007746.PDF

Use bridge rectifire or 6.0 AMP SILICON RECTIFIER diodes like 6A4(very cheap) depending on transformer type.

For regulation see : Power Supply
or
**broken link removed**

 

[vead]

thanks for respons but how can apply formula in circuit to find component rating give example and explain me plz