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do I need a circuit?

donkey

Feb 26, 2011
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http://www.ebay.com.au/itm/120935947271?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
i got 3 of these little suckers and I washoping there would be a nice big label saying voltage in / voltage out.... well there is but the Vout has 3 poles..... then I also saw this component used with a couple capacitors on a circuit board, Now I am trying to figure out if I can simply hook it up to 12v and it outputs 2 5volt rails with a common ground?
 

Harald Kapp

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Check this. It seems that you have to ask specifically for a datasheet to have it sent to you.
 
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donkey

Feb 26, 2011
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Home > Clothing & Accessories > Women > Vest > 10x KIM-055L Step Down DC-DC Voltage Regulator Module
ok thats a fun place to hide the dc-dc step down converters... in with the womens vests, no wonder I can't out anything lol
 

donkey

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http://www.aliexpress.com/store/pro...8A-packet-transfer-3-3V/314688_524734396.html
this page helped a little, I have rough idea on the cap value. but what does "Note: between the input and output to ground to above ground plus a minimum 220uf or 22uf capacitor common point solution of the above solid-state capacitor filter, otherwise the output voltage is not normal and there is noise! Need for special solid-state output filter capacitor:" mean exactly?
the pins on the base of the module read Vin and gnd on one side the other says Vout(this has 2 pins) and Gnd.
I am assuming the gnd beside the Vin is the ground for Vin and vice cersa but the extra pin and no details on the product is getting me confused
 

Harald Kapp

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My guess: that is an automatic translation.

Start with two 220µF capacitors, one from input to GND, one from output to GND. Add 2 100nF ceramic capacitors, in parallel to the electrolytics.

Vout has 2 pins possibly to bettter conduct the high load (a single pin might be overloaded at 5A).
 

donkey

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test1es.png

something like that? and then put 2 100nf caps ontop of the 220µf ones?
that was just a quick sketch sorry if Its bad but I work better with pics
 

Harald Kapp

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Something like that, right.
Observe the polarity of the electrolytic caps.
 

donkey

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yep will do thank you heaps harald. I always getjumbled up with caps and was trying to figure out the differences between the ceramic and electrolytic, thank you wiki lol
 

gorgon

Jun 6, 2011
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Looks like the output capacitor is 220uF and the input capacitor is 470uF on most modules. You should never exceed 1000uF, due to stability. This is general, said on the kgcomp site.
 

Harald Kapp

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Another note: unless this module is insulated from input to output, you should connect both GND pins with a wide trace on a PCB or using thick wire.
AS I menioned, there Vout pins for carrying the high current. So why should a single GND pin suffice? It won't,
 

donkey

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ok thats new. I am turning the net upside down trying to find a schematic using thedevice or a datasheet, nothing as yet. stupid me thought I simply put this on my 12volt battery and got 5volt out.
 

donkey

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will buy the parts thursday and see how I go. harald you are a champion myfriend thank you so much for your help
 

donkey

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hey harald got a question what voltage rating do I need? I can get my hands on some 10v 16v 25v 50v or 63 v I was thinking the 16v range but thought I would triple check
 

Harald Kapp

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It is generally a good idea to have electrolytic capacitors rated at least 50% above the nominal operating voltage of the circuit.
Typically I would chose a 16V type for the 5V output and 25V capacitors for the 12 V input.
But 10V caps for 5V and 16V caps for 12V may be used, too. You risk a bit shorter lifetime, depending on possible overvoltage and how near that comes to the rated voltage of the capacitor.

If you don't want to diversify too much, you can use 16V or 25 V capacitors on both input and output. It's a matter of available space (cost should differ only slightly).

Harald
 
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donkey

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imight go the 25V ones then. ty harald yet again. this is going to help out so much
 
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