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Voltage Control: 20v DC Answered

I am trying to find an electronic part that will take in anywhere between 12-36v and put out a consistent 20v. What could do this? And how can I get one? If amperage matters, I'll probably be putting between 1 and 4 amps through it.

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tech-king
tech-king

12 years ago

3.5 amps? sounds like a zener diode might work.

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guyfrom7up
guyfrom7up

Reply 12 years ago

is that your answer to all electronic regulating questions? I havn't seen you here for a while Glad to have you back Also that won't work when it's below 20 volts

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tech-king
tech-king

Reply 12 years ago

hmmm..... yes, i suppose a zener diode is my answere to regulating questions. and i dont think an lm317 can add voltage.

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V-Man737
V-Man737

Reply 12 years ago

I was thinking a 78xx would work, but I don't know which... Or exactly how to get one (or ten, lol).

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guyfrom7up
guyfrom7up

Reply 12 years ago

I don't know if it exists, but you'd need a 7820. Also those are only like 50% efficient, so half of your battery will go to waste I look into it tommorow, but it's late here

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V-Man737
V-Man737

Reply 12 years ago

It exists! It is cheap! I have made a tiny purchase on eBay to see if it works. Thanks a ton!

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tech-king
tech-king

Reply 12 years ago

you may need heatsinks for prolonged use....

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guyfrom7up
guyfrom7up

12 years ago

you could use 2 or 3 (preferably 3 or 4) lm317 regulators in parallel (cause each one can only handle 1.5 amps max) google lm317, radioshack carries them, they are pretty simple to use, you just need 2 resistors to determine the output voltage. If I were you I'd heatsink them.

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guyfrom7up
guyfrom7up

Reply 12 years ago

woops, my bad, that'd only work if the voltage is above like 22 volts, I'll get back to you on this

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guyfrom7up
guyfrom7up

Reply 12 years ago

actually, I don't know if there's a practical solution at that voltage and amperage what's the application, maybe there's a work around

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V-Man737
V-Man737

Reply 12 years ago

;_;
I'm trying to change power source from wall wart to battery pack. It's a project I've been working on since early June (in fact, the thought process is what brought me to Instructables). If I can guarantee 20 volts from these batteries (3 9.6v packs in series, each varying its voltage based on how charged they are), I'll have one of the best Instructables up in a week or less. The load draws a max of 3.5 amps, but the actual current is sporadic and transient. Thank you for taking the time to think about my problems!

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guyfrom7up
guyfrom7up

Reply 12 years ago

just out of curiosity, what device takes 20 volts!?! what kind of chemistry are the batteries (NiCad, NiMH, Lithium Polymer, Lithium Ion, etc.)

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V-Man737
V-Man737

Reply 12 years ago

I'm using NiCd batteries (actually, the very same ones in my first instructable!) to power a laptop... It will be the best instructable ever! Except I thought I wouldn't need any kind of voltage regulation. So it is going to have some unfortunate complication.

I hooked up both batteries in series to the laptop, making sure they were charged to 11 volts each. My laptop ran on that power for four whole minutes! As soon as the batteries' voltage dropped below 19 volts, the laptop cut short. :-( I'm trying to see how I can utilize another battery pack to give me more time, and then maybe have something that will take the lower voltages and make it into the required 20.