Power supply calculations by vead

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bertus

Joined Apr 5, 2008
20,232
Hello,

I got this in an email from you:

i want to build regulated power supply circuit that has input voltage 230v ac
and output voltage 12dc 20ohms load i know i need transformer, diode,capactior,
and other component but iam not surge what rating
how to find out right value of component and calcuations
As I do NOT reply on emails, I post your question here.
This way the others can reply too.

If you search this forum, you will find a lot of examples.

Bertus
 

vead

Joined Nov 24, 2011
712
sir i want buil power supply circuit with help of fomula but i can not deside what is the right value of componet for example
what is voltage rating of transformer, diode and other component plz help
 

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
sir i want build power supply circuit with help of formula but i can not decide what is the right value of component for example
what is voltage rating of transformer, diode and other component plz help
Wasting time in mails and PM you can get solution by searching for Rectifiers......

OK, as you want to convert AC in DC for this the device is called rectifier..
they are of two types:-
1. Switching regulators ( difficult to build)
2. Linear regulators ( easy to build)

Let start with linear....
step to members will building...
1.voltage rating you need at output side...??
2. current rating...??

If you want a 12V DC and .8mA supply probably...
so, buy a transformer of 12-0 or 12-0-12V of 500mA.
diode 1N4007 which can supply 1A max. at peak reverse voltage of 1,000V.
and a capacitor depends on load rating.
you take it of 22,00uF will work perfect, voltage rating of C should be higher than 20V (at least)

here are some schematic you should try first then use a regulators.
 

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vead

Joined Nov 24, 2011
712
but i want design schematic first and build prectical so i need formula to calculations for component rating
- how can find working voltage of diode transformer capactior-
if i know i/p 230vac o/p 12vdc and 20ohms load
 

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
The ideal principle of transformer:-
Power input = Power output
So, Power = V*I or V^2/R or I^2*R

we will use V*I

Vi/p*Ii/p = Vo/p*Io/p
as Vi/p = 220V
let Vo/p = 12V
we require Io/p = 500mA
so, 220/12=500mA/Ii/p

we get input current Ii/p = 27mA
we don't want to go in these equation will designing....
For finding the value of filter capacitor you need to know load current and ripple voltage, i would say no need to go in this right now....
so, here is the data sheet of 1N4007 which speal every thing about this diode.

if i know i/p 230vac o/p 12vdc and 20ohms load
The current on 20ohm will depent on rating of transformer and diode....
so if you will connect this 20ohms load to different rectifiers the load current would not be same.
 

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vead

Joined Nov 24, 2011
712
if i design circuit transformer+rectifier+capactior+regulatior+load then how can i find total resistance of circuit what concept i learn to need
 

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Why you want to calculate the resistance of circuit..........??
this is no like hybrid parameter of transistor, take it easy first learn basic they move to comple part.....
 

R!f@@

Joined Apr 2, 2009
9,682
Pritesh, u r getting to be quite good at this..eh!.

I guess we'll leave this thread to u to complete. but we will be watching to see if you might need assistance.
 

vead

Joined Nov 24, 2011
712
thanks sir for your responce i read about electronics component and their formulas in books but i want to built circuit i really confused how can apply the formulas
if i know input-230vac, o/p-12vdc, load 20 ohms and o/p current 2amp
transformer+bridge+capactior+regulatior ic+capactior+load
how to chooes diode,transformer, capactior,ic for supply
and working voltage and current for component i want basic concept to build every supply plz suggest me and thanks again........
 
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