# How to convert 12V 1.0 A DC to 3V DC

Discussion in 'General Electronics Chat' started by beingsallu, Jul 14, 2012.

1. ### beingsallu Thread Starter New Member

Jul 10, 2012
18
0
hello every one

I want to convert 12V 1.0 A DC to 3V DC
is that possible if yes . so please tell me

2. ### #12 Expert

Nov 30, 2010
18,076
9,691
It is possible. You can use a voltage regulator or a DC to DC converter.

Jun 22, 2012
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4. ### wmodavis Distinguished Member

Oct 23, 2010
739
151
It definitely possible, in fact that sort of thing is routinely done all the time.
Voltage divider, zener diode, voltage regulator,

Last edited: Jul 14, 2012

Apr 28, 2012
3,682
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6. ### ravishankar kv New Member

Jul 14, 2012
8
1
if output current required is less than 1A then try 7803. better use a heat sink along with that.

beingsallu likes this.
7. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
513
You can get a free finished design for this from National Semiconductor. Use their Simple Switcher software. Schematic, parts list, the whole banana. No heatsink required. part number LM2575-ADJ will work for it.

8. ### crutschow Expert

Mar 14, 2008
23,130
6,860
A linear regulator is simple and will give an output current of 1A maximum @ 3V with a loss in the regulator of about 9W.

A switching regulator is more complex but can give an output over 3A maximum @ 3V with a loss in the regulator of a couple watts or less (depending upon the switching regulator used).

9. ### beingsallu Thread Starter New Member

Jul 10, 2012
18
0
can you tell me circuit schematic of 7803

10. ### #12 Expert

Nov 30, 2010
18,076
9,691
There is no such thing as an LM7803. Use this.

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11. ### takao21203 AAC Fanatic!

Apr 28, 2012
3,682
491
I'd be curious to understand what is so complex about 4 components. Which I never calculate in any kind.

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12. ### #12 Expert

Nov 30, 2010
18,076
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Nice photo. Do you have a schematic of this 4 component switching regulator?

13. ### takao21203 AAC Fanatic!

Apr 28, 2012
3,682
491
Yes. Also LED is added to output + 1K resistor.

Timing capacitor can have different values,
I have measured lowest input current with 68pF.

50pF, 180pF, 470pF etc., all ceramic caps.

If you use electronic transformer, input cap. is not strictly neccessary!

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14. ### #12 Expert

Nov 30, 2010
18,076
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I think I just became a fan of the simple switchers.
I wonder if they can be purchased in New Delhi.

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15. ### tpny Member

May 6, 2012
216
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I would think it depends on what u will be using the 3V for.. When I needed a voltage source to drive two 3.3V ICs, I used an encapsulated DC-to-DC converter (eg, Mean Well DKA15A-05) to step 12V down to 5 then an LM1117. You can also get one to step 12V down to 3.3 in one step. (I needed 5V and 3.3V on the same board.) I'm not sure: could I have done the same with an MC33063/4 like above?..

16. ### beingsallu Thread Starter New Member

Jul 10, 2012
18
0
with using LM317
R1-220 ohm
R2-470 ohm
output-3.92v
.
is capactiors are must for this
if yes tell me which one ?