Help wiring 3 pin adjustable regulator.

[basementcat]

Hello. I am wondering if someone can direct me to how to wire a 3 pin adjustable voltage regulator. Specifically the lm317 or tm317. It's has (from left to right) Vin-adj-Vout. I am just wondering on a pcb where the potetiometer and cap would be wired between. I'm assuming the positive battery runs To the Vin then out of the Vout. But dunno where or what caps and am only assuming I want a 200k pot to adjust it. Any help is greatly appreciated. Can give you my email if you can send me a pic of how to wire it or a good explanation. Thanx.

 

[Para]

Check This Thread....mamu included some killer tutorial info including how to wire.

 

[basementcat]

Check This Thread....mamu included some killer tutorial info including how to wire.

Cool mod he made but I'm looking to wire my own up. He used a premade switching reg.

 

[o4_srt]

Better be using a heat sink, the lm317 gets HOT

you don't NEED caps, just resistors to set the voltage.

To be honest, id look at using a different regulator. It can be done, but it is extremely inefficient. And in order to keep it cool, I needed to attach it to a to-220 heat sink, and use a 40mm fan to circulate air through the sink. Without the fan, the sink would still achieve 70 to 80 celsius after just a few minutes of vaping.

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[basementcat]

Hmm then I wonder what 3 pin that usuable? Any suggestions?

 

[o4_srt]

why does it need to be 3 pin?

Mouser

look for a part that meets or exceeds the following specs:

Vin min: 6 volts or less
Vin max: greater than 8 volts
Vout: adjustable from at least 3-6 volts
Iout: at least 2 amps

the reason that the LM317 heats up so much is because it is rated for a max Iout of 1 amp, 1.5 amps if Vin-Vout is less than 15 volts. Using one in an ecig is right around the max specs the chip is rated for.

LM317 in action: Ultimate Passthrough

its loud, hot, but gets the job done


if you're ok with using something with more than 3 pins, check out the PTR08100W from texas instruments. Available for free as an engineering sample, and boasts 92% efficient at 5 volts.

 

[basementcat]

Well it doesn't absolutely have to be 3 pin but I am looking basicly for the smallest adjustable reg I can get. The 5 pins I have from ti are a bit big.

 

[basementcat]

I actually have 2 different ti ones here now. A ucc383t-adj and ucc283t-adj. They're about the same size as a 3 pin but wiring them to a pcb the pcb would have to be at least 5 wide which is bigger than I'd like but with some creative wiring I could shrink it I think.

 

[o4_srt]

Creative wiring is your friend. The ptr08100w has a footprint about the same size as a standard to-220 package (lm317 style). The board I made for mine is no wider than an lm317, and including the regulator, is about as long as 2 of them.

I know you want something as small as possible, but there are trade-offs.

The ucc series chips are perfectly suitable, but being linear, create heat as well, but not enough to need a heat sink. When I get home from work tonight, ill send you a link to a mod using that chip that spells everything out.

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[basementcat]

Awesome! Very new to electronics wiring and construction and just looking to make some variable volt mods for friends and family. Your info is greatly appreciated!