Differneces between these servo/motor driver boards?

Can anyone shed some light on the differences (and why) between these servo driver boards?

They all look the same.. but where the screw terminals are.. they each vary slightly.

They all use the same PCA9685 based chip.

Adafruit version: https://www.adafruit.com/products/815 * no screw terminal - (no biggie) * has a big....transistor? (maybe its a voltage regulator though?) * no big cap (but footprint for it)

Ebay - 1 version: http://www.ebay.com/itm/121651185889?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT * has screw terminal * no big cap (but footprint for it) * has a smaller transistor? (mirroring the Adafruit).. but its a smaller component with some caps/resistors and an LED (Adafruit version has no extra components)

Ebay - 2 version: http://www.ebay.com/itm/201402794566?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT * has big cap * has screw terminal * missing ANY sort of transistor (big or small?) * seems to have cap/resistor/power led by screw terminal..

I have one of the LAST ones.. but upon research I noticed these other variants.. and the differences.

Can anyone shed some light as to WHY these all have slight differences? (and what one would be the best?)

I guess the main difference is that 'transistor' (??) either missing, being big or being small?

Thanks!

The Adafruit one comes with terminal block and headers, but not populated so you can populate what you need or solder direct.

The eBay ones are knock-offs which may or may not have genuine PCA9685 chip.

Thanks MarkT-

Yeah the screw terminal is kind of a no-brainer.. (but wanted to add it int he list of differences)

I guess I'm more so focused on the 'transistor'? (if it even is one).. the difference in sizes/transistors... and the lack of one on the other board.

I understand about clones and the possible negative effects....

thanks!

The adafruit board uses the transistor for polarity protection. There is space reserved for a capacitor if it is required for sagging voltage. You may/may not need it and the value is dependent on the number/power of the servos.

I just bought one of them for some future project I don't know about yet

ok.. thanks.

So:

1.) It IS in fact a transistor (wasnt sure if maybe it was a voltage regulator or something)

2.) The 'clone' board I got.. (with NO transistor footprint on the pcb.. small or large).. should be ok.. if I'm mindful of the polarity.

xl97: 2.) The 'clone' board I got.. (with NO transistor footprint on the pcb.. small or large).. should be ok.. if I'm mindful of the polarity.

Probably better than ok, since the cheap clone would have used the cheapest part they could source which would have turned into a liability within 10 uses of the board. The clone improved it's reliability 100% by eliminating 1 of the 2 components on the board!!!

tinman13kup: Probably better than ok, since the cheap clone would have used the cheapest part they could source which would have turned into a liability within 10 uses of the board. The clone improved it's reliability 100% by eliminating 1 of the 2 components on the board!!!

LOL.. good point!

(someone at my local makerspace has an Adafruit version he is getting to me as well now)

tinman13kup: Probably better than ok, since the cheap clone would have used the cheapest part they could source which would have turned into a liability within 10 uses of the board. The clone improved it's reliability 100% by eliminating 1 of the 2 components on the board!!!

No, they likely reduced the reliability by using reject or cloned parts for the main IC, probably...

MarkT: No, they likely reduced the reliability by using reject or cloned parts for the main IC, probably...

Of course. Reminds me of the "factory overrun genuine Roulex" watches at the fleamarket