dc to dc converter (12V to 3V)

[lightelectro]

hello, sino po ba may circuit nito? kasi gagamitin ko sa kotse na 12V battery. gusto ko kasi i power ang small fm radio na 3V. unang ginawa ko ay potentiometer, voltage divider. meron paba kayong ibang masa suggest? 

[beginner wan]

pwede ka pong gumamit ng LM317.. pwede mo maset yung regulated output voltage sa kanya from 1.25 to 37 volts IIRC.. 

[lightelectro]

thanks po. what do you think sa paggamit nang potentiometer as a voltage divider circuit? 

[1110000]

thanks po. what do you think sa paggamit nang potentiometer as a voltage divider circuit? 

...................................... bad practice

[beginner wan]

hehehe.. tama si totoy.. saka kasi, pag nagbago yung input voltage, magbabago din yung output mo.. saka kung di ako nagkakamali, sayang yung ibang power at nagiging init..

[lightelectro]

yap. thanks. try ko mga 500k na potentio. hindi pwede kasi maliit na ang current. thanks. meron pa naman akong regulator na 317. thanks. 

[underprezzure]

hehehe.. tama si totoy.. saka kasi, pag nagbago yung input voltage, magbabago din yung output mo.. saka kung di ako nagkakamali, sayang yung ibang power at nagiging init..

Tama ka waste of power nga ito. but there is a solution. especially when other components runs at 12V and others runs lower from it and if you need a single power source. Here is the solution. Use a switching regulator before the voltage regulator. 

-underpazz campaigns for more post on technical threads

[glutnix_neo]

...................................... bad practice

bad practice daw oh, parang may nakita ako dati bata na ngpost na inisasuggest yun dati, hehehehe,
masearch nga yung post na yun

[engineer7@home]

hello, sino po ba may circuit nito? kasi gagamitin ko sa kotse na 12V battery. gusto ko kasi i power ang small fm radio na 3V. unang ginawa ko ay potentiometer, voltage divider. meron paba kayong ibang masa suggest? 

For efficiency and simplicity, pwede kang gumamit ng buck regulator.  Marami kang pag pipilian sa www.maxim-ic.com.  Wag mo lang kalimutan na mag lagay ng inline fuse from the battery papuntang buck regulator.  Also please use the right size of inductor and capacitor to minimize the noise. In addition, use a schottky diode like a 1N5819 and not a 1N4001 for efficiency if needed in the circuit.
If this helps, please give me a pogi point.

[badalicious]

pwed po phingi ng circuit ng 12v-3v converter using lm317.tnx po