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[on:]

I couldn't pass on this little gem. Specs look pretty good. I will let you guys know what I think about it once it arrives and I have a chance to play with it. I mostly wanted something to experminate with my 'bandgap' A/D auto-calibration function and needed a way to vary Vcc power to my Arduino board by small repeatable increments. Linear voltage regulators are so 1980s 

 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220648404910&ssPageName=STRK:MEWNX:IT


Lefty

[Reply #1 on:]

The description says "Low output ripple makes it performs more perfect."

The ripple comment has a context. When I first looked at this item about a month ago he also offered an identical looking module that he rated at 40-60mv of ripple voltage for maybe $2 less, and stated that he sold a different one (this one) that had better ripple spec. I looked at the spec sheet for the chip used and the output filter cap's quality seemed to be the biggest factor in ripple, but he kind of implies that the country manufacturing the chip is the main factor? Who knows really. I do have a scope so I should be able to verify ripple voltage when I check it out. I recall from my field service days that the better commerical linear power supplies in the 70s and 80s were all rated at around 7mv ripple content. Brands like Lambda ring a memory from long ago.

Lefty

[Reply #2 on:]

I've ordered from Satistronics in the past and they have been quite good. I even have two of the aforementioned DC-DC switching power supplies, if you buy directly from Satistronics, you pay about $3 less each.

[Reply #3 on:]

I've ordered from Satistronics in the past and they have been quite good. I even have two of the aforementioned DC-DC switching power supplies, if you buy directly from Satistronics, you pay about $3 less each.

Have you been happy with the supplies? Do they seem to meet all the specs given?

[Reply #4 on:]

Yes, they have been very good. I haven't had a problem with either of them.

[Reply #5 on:]

Mine arrived after just six days, that's a record for me for stuff from China to west coast. I have been very pleased with the quality and it works as advertised. Now I need to find a wall wart supply at a thrift store of say 24vdc @ 2amps and I will have a nice variable 1.2-22vdc regulated and current/heat protected supply good for a couple of amps. A heat sink could push that to 3 amps they say, but I haven't pushed it so far.

Looks like they added an addition LC filter on the output of this board, not suggested in the datasheet, for the better ripple spec they are getting.

 Anyway, I'm happy and certainly think they are worth the $10 including shipping and I have no problem recommending with module.

Lefty

[Reply #6 on:]

Looks like they added an addition LC filter on the output of this board, not suggested in the datasheet, for the better ripple spec they are getting.
Lefty

The inductor is not a filter but actually part of the switching system.

... I doubt you want to know the hoary details  

P.S.
You get best results when the input voltage is about twice the output voltage.

[Reply #7 on:]

The inductor is not a filter but actually part of the switching system.

I may not have stated my observance well enough. The datasheet for the switching regulator shows the use of just one inductor. The actual board I have in my hands has two inductions, the larger main inductor and a second smaller one that along with a small capacitor forms an additional low pass filter right at the DC output terminals.

 Sorry there is no schematic from the vendor for the board to post here, but as best as I can determine it follows the datasheet application example except for the additional LC filter on the output.

Lefty