new to electronics (circuitry)...need help!

[RichRymer10]

I know that if the supplied power is more than the max rated for a component, u use resistors. so wut if the power is less? is there something u have to put in between the object and the power? The power i have is 12 volts and the thing i wanna connect is 15 volts. i know that u cud connect it regardless but i want maximum efficiency.

 

[FattyMcNastyXK]

coulding you feed the 5 volt line into the same thing?

 

[Stedeman]

Its called a transformer but it will cost you Amps and if you don't know what your doing your better off buying a pre fabricated power amplifier

 

[TyRex]

what exactly is this that requires 15volts........may helpto understand your needs

 

[RichRymer10]

its a peltier. i wanna experiment with a 85 watt first.

 

[stool]

DC\DC converter. Check some of the electronics sites.

 

[Temo Vryce]

The transformer will only change the voltage if you're dealing with AC not DC. The idea to connect the 5v line would work as well but you would have to connect it in series with the 12 v line. If you're unsure how to do this I would suggest buying a cheap power supply.

 

[TyRex]

A transformer will put out any type of current you send you through it......if AC goes in the primary, then AC comes out the secondary.....if DC goes in the primary, then DC comes out the secondary..... you can run a 15 volt pelt at 12 volts if you like. It won't be working at its best level, but it will still function well

 

[dagamore]

TyRex, transformers, can not send dc power through them, it is because of how a transformer works. with dc, you will get a spike when the dc power is applied, and then aother one when it is turned off, but you will not get continual power pass through. that is why they work so well as ground fault isolators

 

[four4875]

yeah, transformers work on AC and pulsing DC (like use a diode on one side goin in to it) but not on straight DC, because theres not an expanding and collapsing magnetic field on the iron thingy

the pelt will run fine at 12V, just not as much heat transfer as ultimately possible.

 

[Annoyingrob]

Transformers work on the principle of a changing magnetic field inducing a current in a conductor. The key word being "changing". a direct current will not be able to induce a current within the secondary side of the transformer. If I remember correctly, electrons will flow if there is a difference in the magnetic fields between two conductors, causing the electrons to move to adjust. you need a constantly changing current to induce another current, or else you would just get a spike when you apply, and remove power.

Enough beating of the dead horse.........

Id suggest running the pelt at 12v for now, or link up two psus, like a 5 and a 12, or adjust output trimmer pots if it has it. Pelts generally run most efficient at 80% rated input if I remember correctly. That's not to say more voltage wont make it colder, it will just generate a lot more heat on top of that..

bTW, the "Iron thingy" would be a ferro-magnetic core, a soft metal which is easilly magnetized and demagnetized

 

[LuckyBob]

You can throw DC into a transformer, but only if you put an AC wave construction circuit just before it ^_^

This isn't exactly practical for something like a peltier anyway. If you really want to have +15VDC into your pelt, grab a book on building power supplies. I'll forewarn you that high amperage transformers are fairly hard to find, though.

 

[TyRex]

hmmmmm.....I my understanding must be flawed......thanx for the correction though

 

[Annoyingrob]

I wasnt trying to criticise or anything, it's just a learning experience.

 

[TyRex]

no offense taken.........

 

[four4875]

if you build an AC circuit, you wouldnt be puttin DC into the transformer, you'd be puttin AC into it :-D