FREE DC-DC CONVERTERS!!!

timmeh87 · Post by **timmeh87** » Thu Feb 16, 2006 5:45 pm

gforce- sounds exactly like something a nice, big capcitor would fix.

also, if you are using a digital multimeter, it averages over 1 or 2 seconds, it wont pick up spikes like that.

G-force · Post by **G-force** » Thu Feb 16, 2006 6:13 pm

Thanks. So I should use a bigger electrolytic or a bigger ceramic cap? The ceramic seemed to make no difference, so I guess I'll try a bigger electrolytic. I have a 470 uf, that's pretty big, so I'll give it a shot.

EDIT: Nope, no difference at all with a bigger cap. Arg...

timmeh87 · Post by **timmeh87** » Thu Feb 16, 2006 9:22 pm

hm. well its obvious that the burst of power needed for a big bass hit is what is causing this. and the way to solve that is usually capacitors. perhaps dedicating a nice juicy one right near the audio amp... on my brothers screen there is space for capacitors that was never used. he fixed his problems by putting some there (those cheap bastards... always cutting corners...)

and, just as an experiement (this is what i would do), maybe see what happens if you locate like 5mF (ten 470uF's in paralell... ok this is a bit excessive) of capacitance near the dc-dc.

Neildo_64 · Post by **Neildo_64** » Wed Mar 08, 2006 7:55 pm

I think this topic should be stickyfied so it doesnt get lost like some of the other useful posts. As long as people dont take advantage of the "FREE" part. I'd say If you need one for a portable, or maybe two, go for it, but dont try to order 30 just because they're free samples.

Post by **Triton** » Tue Mar 21, 2006 3:09 pm

i have a question, would a 47uf EC cap work to clean up the signal? i agree on stickiness too btw

blackbox_dev · Post by **blackbox_dev** » Fri Mar 24, 2006 7:40 pm

Yeah, why isn't this a sticky?

daguuy · Post by **daguuy** » Fri Mar 24, 2006 7:44 pm

there's a link to it in the sticky

Post by **Skyone** » Mon Mar 27, 2006 9:20 pm

Question!

What'll happen if I DON'T use any caps with my regulator?

Post by **marshallh** » Mon Mar 27, 2006 9:29 pm

Well, for me, it makes absolutely no difference. I still get video interference. However, I'm sure it does make a difference somewhere.

Post by **Skyone** » Mon Mar 27, 2006 10:11 pm

Oh, so the reason that the caps should be there is because it'll screw up the video?

JAY · Post by **JAY** » Mon Mar 27, 2006 10:24 pm

The capacitors reduce the amount of fluctuation of the input and output voltages, so as to keep them steady. For example, if your input voltage dips or is cut off for a brief moment for some reason, then the input capacitor will discharge to keep the voltage to the input roughly the same, so as to not have the regulator/convertor shut off during that time.

Post by **Skyone** » Mon Mar 27, 2006 11:19 pm

Ok thanks! For the cap(s);

Is it ok if I only use one cap?

Can it be 100uF and electrolytic?

The pin next to the strip of the lighter blue, arrows pointing to it, and boxes is NEGATIVE, right?

JAY · Post by **JAY** » Mon Mar 27, 2006 11:44 pm

A 100uF electrolytic capacitor on the output side is what the spec sheet calls for. The input capacitor is optional, so you only need the one for the output.

The short pin is the negative side. Although this cap is labeled with the bars and arrows to signify the negative side, some of them might not be, so that's a good thing to remember.

Post by **Skyone** » Mon Mar 27, 2006 11:56 pm

Oh, well I just soldered the 100uF to the Regulator assuming that the strip/arrow side was negative.

It gives me a steady 3.3v!

If I reversed the polarity, would it not give me 3.3v? Just to be safe.

JAY · Post by **JAY** » Tue Mar 28, 2006 12:14 am

I think you misunderstood what I meant.

The short pin is the negative side. It always is. If the cap is labeled with the bars to signify the negative side, then it's easy to determine which pin is negative. But some devices might not be so explicitly labeled (such as LEDs), to let you know which pin is which. In those cases, it's good to remember that the short pin is negative.

I hope I cleared that up.