urn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f8249 2017-07-14T05:04:07-06:00 SparkFun Electronics Customer #851722 urn:uuid:b5a2b6ec-efa6-2a88-88bb-e5ef51b09797 2017-04-17T07:43:25-06:00 <p>Shouldn&rsquo;t the PWM value on a Arduino not be 0->255 instead of 0->1023 like in your example code?</p> Customer #864870 urn:uuid:0aea36dc-ee30-ab6f-0573-61e6b7e4a5ee 2016-11-11T15:37:04-07:00 <p>what the value of BTZ52? 20V? 25V? and how many Volts are enough for the 560uF caps? all resistors with 5% tol its ok?</p> <p>the mosfet FDD8580 can be the FDD8780? (the zener have to be different?)</p> <p>and why the 2 cap 1000uF on pcb and not in the board?</p> bboyho urn:uuid:119b837a-0cda-b0e1-c087-39ac8530d17a 2016-08-29T14:51:39-06:00 <p><strong>&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&ndash; Tech Support Tips/Troubleshooting/Common Issues &mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&ndash;</strong></p> <p><strong>Shorts?</strong></p> <p>After soldering the 5mm pitch screw terminals, try adding electrical tape on the bottom of the soldered terminals so it does not short with the pins on the Arduino.</p> <p><strong>Additional Example Tutorial and Reserved Pins</strong></p> <p>Quick tutorial explanation => <a href="http://garagelab.com/profiles/blogs/tutorial-how-to-use-the-monster-moto-shield" rel="nofollow" >http://garagelab.com/profiles/blogs/tutorial-how-to-use-the-monster-moto-shield</a>.</p> <p>Besides power, it just uses 2 analog pins, 4 digital pins, and 2 PWM pins to control the motors.</p> Customer #780317 urn:uuid:70bc6d4b-0eab-c3c7-c015-edd13ac1fcdd 2016-07-20T19:27:27-06:00 <p>look like my comment has been &ldquo;purged&rdquo;&hellip;&hellip; sad!!</p> Customer #695247 urn:uuid:762421dd-5e59-fab3-ce12-5477a057bc69 2015-07-09T22:50:28-06:00 <p>Can someone explain how do I find the correct value for CS_THRESHOLD, what pin 13 (statpin) does and how to use it?</p> Customer #695247 urn:uuid:f98007ad-bb2b-4de6-0c01-f35416dc1040 2015-06-27T00:07:26-06:00 <p>How could we add some extra layers of protections between arduino, this shield and the motors. Would this circuit work for using separated power supplies for both boards and opto isolators to isolate them?: http://i.imgur.com/1JbWVmr.png I can make sense of parts of it but I don&rsquo;t understand how it can work when all the collectors of the opto are connected to the same Vin, so all the pins seem basically bridged. What about the motors, is there any circuit you guys could share to protect against inductive kickback? I know the board has built in protections, but I know some people that burnt a few of them, and that makes me paranoid.</p> Customer #437992 urn:uuid:b9383990-693d-8d14-8e60-e81ee44d1415 2015-05-07T21:14:10-06:00 <p>Because this shield uses pins 1 and 0, it&rsquo;s not compatible with Yun, correct?</p> Kamiquasi urn:uuid:b7f1daeb-72e8-80d4-9ef4-6834e8ffda9b 2015-05-05T02:56:55-06:00 <p>My memory doesn&rsquo;t go back four years on these topics, I&rsquo;m afraid - but google+hackaday does: <a href="http://hackaday.com/2011/08/17/a-stackable-motor-driver-shield-for-the-arduino/" rel="nofollow" >a stackable motor driver shield for the arduino</a></p> Jdude2345 urn:uuid:404639b8-5c2d-d7d3-461d-667231a0c24c 2015-05-04T22:19:35-06:00 <p>Just like the Adafruit one? https://www.adafruit.com/product/1438</p> Customer #664228 urn:uuid:881db322-5217-df58-1689-73a5b7bb8626 2015-03-24T09:32:54-06:00 <p>Stupid question- are these stackable?</p> Customer #651227 urn:uuid:b4afbb00-e27a-fa6b-f6ce-0ca346e3e59a 2015-02-17T06:26:56-07:00 <p>Sorry, but how can I connect this board to any stm32 board? It looks like a good idea to connect EN pins directly, INAs &amp; INBs through Logic Level Converter (with BSS138), but how to connect PWM inputs? Main problem, as I understood, is that PWM inputs has pull-down resistor&hellip;</p> M-Short urn:uuid:6580c260-42c4-e25b-e5e9-f716a5be66c3 2014-12-15T11:37:04-07:00 <p>No, this is an Arduino shield. Check out the <a href="https://www.sparkfun.com/products/11561" rel="nofollow" >RaspiRobot Board</a>, that might work for your needs.</p> Customer #488710 urn:uuid:15a4a075-1c18-d95c-95bd-d4ca10397f6c 2014-12-14T10:01:37-07:00 <p>Is it compatible with the Raspberry Pi?</p> Knutson urn:uuid:75985760-26b6-5204-0e22-a03590dc9444 2014-12-12T15:08:21-07:00 <p>You&rsquo;d be surprised how many mimicking products we run into on other website retailers. If you&rsquo;re looking to buy a genuine Sparkfun product from somewhere else, but you&rsquo;re unsure whether it&rsquo;s from us or not &ndash; you can always give us a holler at techsupport@sparkfun.com</p> Customer #409067 urn:uuid:3235e0cb-ab5d-db3f-0576-091058541b36 2014-11-10T20:37:58-07:00 <p>I am confused on how to wire this shield to a motor with encoders, does anyone knows? Does inApin and inBpin have anything to do with the motor&rsquo;s encoders or is it separate ?</p> <p>I am these are stupid questions, any good tutorial would be appreciated.</p> Customer #319321 urn:uuid:14f60798-99bb-49e0-c62c-cc5abdc41ad5 2014-08-03T23:34:25-06:00 <p>I have a PcDuinov2 (GPIO - 3V3). Could I use it directly with this shield or I will need a voltage translator 3V3 to 5V?</p> Customer #526708 urn:uuid:3cd2bc7b-2883-aad6-69f3-458ece92c8a0 2014-03-03T18:44:27-07:00 <p>with them, what you see , is probably not what you get&hellip;</p> Customer #450381 urn:uuid:be3834fb-161e-ee30-0bc8-266d451684f0 2013-06-28T13:12:20-06:00 <p>hello people I&rsquo;m trying this code to make the motor turn to the right or left via potenviomentro, starting on low speed and as for increasing the graduation of the motor potentiometer will also graduating, if you make a smooth torque in the motor potenciomentro also starts soft but if you do a fast torque in the motor drives potenciomentro too fast, but the only thing I got is that the LEDs remain lit direct and very weak when I turn the engine off if the LEDs, since the potentiometer does not trigger anything like the help of the staff thanks</p> charlesgg urn:uuid:5ab2a6d1-99df-5f1f-7186-ccedd29c9574 2013-05-24T05:36:29-06:00 <p>Yes it works. Just set the PWM pins to output and HIGH. For example the stepper_oneRevolution example works with this setup: Stepper myStepper(stepsPerRevolution, 7,8,4,9); void setup() { myStepper.setSpeed(300); pinMode(5, OUTPUT); pinMode(6, OUTPUT); digitalWrite(5, HIGH); digitalWrite(6, HIGH); }</p> <p>But since there is no hardware current limiting, steppers get hot real fast. And since the drivers do not work at low voltages such as 3V that are suitable for a lot of steppers, that can be a problem. Solution: get 12V steppers. Better solution: get a stepper driver with current limiting.</p> Mat! urn:uuid:c4c7d6f4-ff9d-4229-9c84-2d93476d3209 2013-03-18T02:25:01-06:00 <p>Hello Sparkfun ! I have the same question as Member #86519 and i didn&rsquo;t found the answer into the sample code : &ldquo;How can we convert the value read by the Current sense ANALOG input Arduino&rsquo;s pin into current intensity ?&rdquo;</p> <p>thanks Mat</p> Kamiquasi urn:uuid:c4b6638f-2fe5-0201-91c2-3d7bc3616b5f 2012-10-24T19:33:26-06:00 <p>Hah. I guess if they&rsquo;re gonna take the Eagle files to do their own run, they might as well be blatant about it. At least for Pro Mini they left the logo on ;\</p> Dibblah urn:uuid:11bc5722-8cea-1048-8129-d1d69073b27c 2012-10-24T14:26:20-06:00 <p>http://dx.com/p/monster-moto-shield-for-arduino-red-161274 - Not cool, DX - Not cool.</p> skumdog urn:uuid:fc67f2e0-2774-a6d3-7654-df49c68d4b05 2012-07-21T19:25:06-06:00 <p>http://www.pololu.com/catalog/product/2502 This one here does have the arduino pin layout.</p> Customer #339369 urn:uuid:b8458872-936f-81ca-95d3-0db5c63e5b48 2012-07-19T14:50:15-06:00 <p>Can I control a stepper motor with this?</p> DmitryS urn:uuid:4dcd3e79-fcd4-6b33-1384-a7b4036d7811 2012-05-29T08:00:41-06:00 <p>What for are these FDD8580 mosfets are used? Only for reverse polarity protection or what?</p> Customer #86519 urn:uuid:360cc0f0-cc18-2d30-fd06-0e61373127f3 2012-05-15T16:56:06-06:00 <p>What is the conversion for the Current sense to read amps on the Arduino?</p> <p>This is what I calculated, but its way way off!</p> <p>V=ADC_steps * (5/1024)</p> <p>I = V/1.5kOHM</p> <p>I = (ADC_steps * 5)/1024)/1500</p> <p>I = ADC_steps/307200</p> <p>But what I measured is way way off&hellip;</p> <p>Through trial and error I found the constant to be 30.56&hellip; However I don&rsquo;t know how accurate that is because I measured the current with a MultiMeter.</p> <p>Is it me or is there a mistake in the data-sheet? shouldn&rsquo;t Rsense be 1.5ohm instead of 1.5kohm&hellip; which would be 30.72 for the constant?</p> charlesgg urn:uuid:d51de211-f736-8c9b-0892-f577755f41ec 2012-03-01T03:41:07-07:00 <p>Hi, good to see you changed the 40V to 16V in the description.</p> <p>I tried mounting 5mm screw terminals, and they overlap the H-bridge ICs. Please update the design for the next batch.</p> SJL urn:uuid:95d395dc-2c73-4915-0fd7-8b0dbb7d0da8 2012-02-27T16:32:51-07:00 <p>Should this work in a stack with Arduino UNO and XBee shield?</p> jbaker urn:uuid:d9e99b2d-4600-23b3-eaf4-31849a403e10 2011-11-21T20:57:57-07:00 <p>Given the price tag and the width of the output traces, am I correct in assuming that this board is manufactured very high copper thickness? To handle the full 30A with those output traces, you would need something like 6oz copper. Using a more ordinary 2oz copper PCB, those traces can only handle about 12A. If nothing else, that would explain why it costs so much for ~$25 of components.</p> <p>Trace width calculator: http://www.4pcb.com/index.php?load=content&amp;page_id=95</p> RobertC. urn:uuid:6ace5023-5db9-7a34-891c-792b7cb748b0 2011-09-30T13:54:36-06:00 <p>Ah ok. Then this should work.</p> TECH GEEK urn:uuid:8300bab5-7eef-442a-e92d-0748e11e95cd 2011-09-30T13:54:00-06:00 <p>there are only 2 channels. aka, two sets of 3 motors wired in parallel&hellip;<br/> would it still be able to handle the current?</p> RobertC. urn:uuid:d6a6cbb1-2041-2084-9f4f-8e9bc706d998 2011-09-30T13:45:30-06:00 <p>Yes, but you&rsquo;d need 3 of them for all 6 motors.</p> TECH GEEK urn:uuid:b673956d-3b23-c7a2-5e4a-afc9cd4e6a68 2011-09-30T13:32:33-06:00 <p>Will this work with a <a href="http://www.pololu.com/catalog/product/1563" rel="nofollow" >dagu 6WD chassis from pollou</a>?<br/> Basically can this board handle the following: ((7Amps<em>3Motors)</em>2Channels)<br/> Also can this board pulse the motors?(PWM)</p> cyberteque urn:uuid:d3a34dc8-e1a2-fefa-1b8d-e02c88a6cf97 2011-09-21T09:32:36-06:00 <p>I bought one of these &lsquo;coz I got a 4 motor Rover 5.<br/> After looking at the board in mah hand&hellip;<br/> There is NO WAY IN HELL I&rsquo;m going to put it over my Arduino!<br/> I&rsquo;ll mount it away from my Mega and just run ground, +5V and the control lines to it.<br/> There is just not enough clearance on the motor supply.<br/> I only got this to run my Rover 5 after I figured out 1 L298 per motor was not going to be enough.<br/> So @ 6A it looks ok</p> Customer #143099 urn:uuid:6024aec0-a265-eb34-b253-d0bc81ce3ff3 2011-09-20T06:47:39-06:00 <p>This board design is ridiculous !<br/> those ships are designed to hold 1000W of power EACH.<br/> and the board could support 20W maximum.<br/> Fan will not help much, the dissipation of the chip is from below.<br/> It is like putting two jet turbines inside the trunk of a Nissan Micra, with the hood closed.</p> Kamiquasi urn:uuid:b3cd3afb-e146-48d0-72c1-d17e3c5ffcc8 2011-08-19T06:47:42-06:00 <p>If you&rsquo;re interested in an alternative, one of the #sparkfun frequenters is making a stackable motor shield so you can drive as many motors as any project may need. Just google for the key words there - it was recently covered on hackaday so I&rsquo;m sure it&rsquo;s easy to find :)</p> tinito urn:uuid:0cdd9c6d-2ce6-431b-9134-55922701a287 2011-08-19T03:49:27-06:00 <p>79$ for two 10$ PWM drivers and a 30-min imprecise routing work? Awesome!<br/> At least try to give correct usable specs instead of misleading absolute maximum ratings. And specify that you misplaced the two leds, they are going to burn at first >5V use.</p> Customer #59999 urn:uuid:fc4378b4-a0c1-1106-16a8-cbeadb97cdbf 2011-07-31T19:06:01-06:00 <p>Customer service had an interruption while they migrated to new servers - Upshot I did get good customer service and a replacement shield!</p> frada urn:uuid:b5cfd2ce-63fb-cbe1-8f76-63916d2dc4bc 2011-07-31T13:42:43-06:00 <p>OK, some experiments just done with this circuit and I concluded that definitely it does not do what the features section promise:<br/> - first of all the maximum voltage of 41 V is not usable at all due to the internal overvoltage limit of the driver IC (as already said by Member48425 in his/her comment). As specified in its data-sheet, the VNH2SP30 IC is for automotive applications for which the nominal working voltage is 13.8 V or so. The 41 V limit is an &ldquo;absolute maximum rating&rdquo; specification for VCC, that is the maximum sustainable supply voltage by the internal H-bridge. In my experiments the drivers gone in protection mode disabling the output when VCC rose over about 16 V and the only way to recover a normal operating condition was to switch OFF and then ON again the power.<br/> - The current limit resistors for all LEDs are valid only for VCC of about 5 V! When I first saw the schematic diagram I though the values were wrong, but when I supplied the circuit a 24 V&hellip; they burnt in a few seconds, so I was forced to desolder them.<br/> Definitely this shield was not a valid choice; I think I could find some more valid product for my needs!</p> frada urn:uuid:42ff8158-48dc-6e66-6835-9dd78d468729 2011-07-29T12:32:47-06:00 <p>I bought one Monster Moto Shield and one ArduMoto Shield from a Sparkfun distributor and&hellip; I discovered that the stackable connectors and the screw terminal blocks are not included in the kit.<br/> OK&hellip; one can say that they are not present also in the published pics, but why don&rsquo;t put a note in clear evidence (or in more evidence in case it is already there and I was not able to see it) on the description of the units?<br/> Now I have two circuit which I cannot use until I receive the missing connectors that I ordered with additional shipping expenses&hellip; this is time consuming and truly frustrating!</p> Customer #59999 urn:uuid:f16ad1b1-00df-f8b4-9fee-7f1c3bba9092 2011-07-12T21:03:06-06:00 <p>I bought one of these, and the second controller does not work within the 30 day return period and customer service did not respond to my email. :(</p> Customer #24524 urn:uuid:f8e6e625-ae4d-683a-be3a-b3ac9fee11e6 2011-06-21T09:01:31-06:00 <p>So is there a Sparkfun motor controller board which could drive two 24V geared wheelchair motors? At full speed with no load, they pull around 2A, but, of course, they can spike much higher and can pull around 10A with a decent weight load.</p> Customer #48425 urn:uuid:dec67557-4976-1f53-ab14-d1ea7ffeb868 2011-06-15T11:19:15-06:00 <p>These H-Bridge ICs do not support 41V. I have worked with them and TI mentioned 41V in the datasheet, but over-voltage shutdown is at 16-22V.</p> Settorezero urn:uuid:63a91e31-b411-7307-cff1-54dc04319b23 2011-06-02T02:56:59-06:00 <p>30A of maximum current rating and the 6A value in the note are the total or are the value for only one motor?</p> charlesgg urn:uuid:78f354dd-9dec-67c3-575e-46fa1d253757 2011-06-02T00:58:58-06:00 <p>So I can&rsquo;t use it with a 36V 12A motor ?<br/> If so please update the product description with real-world data, not absolute-maximum-ratings. Please confirm that, I may return the product.</p> Ward urn:uuid:0843714f-b5cc-7f20-03b3-ec56a17b2ad9 2011-06-01T09:51:38-06:00 <p>Indeed, that&rsquo;s a fine solution!</p> RobertC. urn:uuid:b83051b3-987c-7062-55f2-315161010e8f 2011-05-31T15:14:01-06:00 <p>Correct. Reading the datasheet is always a great idea before starting a project.</p> RobertC. urn:uuid:449b1b8a-7801-78c5-80f4-c7cdc8a050f2 2011-05-31T15:12:10-06:00 <p>It&rsquo;s in both.</p> Ben9 urn:uuid:5e064cbe-fa18-f936-6188-20d8dd69ec7f 2011-05-31T13:49:09-06:00 <p>The current and voltage ratings presented in the description are a bit misleading. While the driver can survive 41 V, it should not be used with voltages above 16 V because that is the point at which the overvoltage protection can kick in. Similarly, while the drivers can deliver a maximum of 30 A, they will overheat at much lower currents without the addition of a heat sink.</p> JoshFranz urn:uuid:668aadd8-4c5c-1dbd-42f9-51bdd83c8a9f 2011-05-31T12:29:02-06:00 <p>Even better, run them off 5V, switched with a FET from Vcc</p> JoshFranz urn:uuid:667cb3d8-f312-1163-7efb-b4ac8e9aba83 2011-05-31T12:28:09-06:00 <p>true.</p> JoshFranz urn:uuid:70380a5a-cdf6-29ea-c693-7c0639508fb5 2011-05-31T12:27:40-06:00 <p>HOWEVER, THIS PRODUCT IS ALSO AN ARDUINO SHIELD, THUS IT ALSO BELONGS HERE. QUITE THE PREDICAMENT.<br/> &hellip;WHY ARE WE YELLING?</p> Polux urn:uuid:ce5bc573-cad9-7f72-732f-7a7e3e8a8d06 2011-05-31T03:29:46-06:00 <p>GND seems not very well designed: it is connected with GND comming from Arduino. Current returning to power supply will use this path if GND is unconnected on power connector J3. Small copper traces will literaly burn, acting as a fuse.<br/> And GND trace width and route is not very straight to JP3. It will not be a problem at some amps, but with both drivers on at 30 amps&hellip;.. :-(</p> HungryMaggot urn:uuid:7e29e587-0c65-3b82-3c5c-b8f62d8ab33f 2011-05-30T00:01:51-06:00 <p>THIS PRODUCT SHOULD BE IN Robotics| Drivers CATEGORY, THIS IS NOT AN ARDUINO, THIS IS A MOTOR DRIVER</p> Ward urn:uuid:c5bedf9d-83c8-60fd-d8d2-b2f3bce94662 2011-05-29T11:14:17-06:00 <p>Thanks for pointing me to the datasheet&hellip;you&rsquo;re totally right, it&rsquo;s reverse voltage protection. I should&rsquo;ve started there rather than spouting off based solely on the schematic. The FET/diode/resistor combo is in the application schematic in Figure 32, and section 3.1 addresses reverse polarity protection approaches. Cap negative to the H-bridge ground, as you point out, and it should be fine. Need a different FET though, as Abs. Max VDS for the FDD8580 is 20V.<br/> All that leaves is the LED1/R20 path&hellip;what&rsquo;s LED1&rsquo;s reverse breakdown voltage (often 5V-ish) and what happens when you run 120mA backwards through him? Tying his cathode to the bridge common would solve that problem too. Finally, even in normal operation, at 41V all of the LEDs will be subjected to ~120mA forward current, likely at least double their rated capacity. Bigger resistors (intensity issues at lower Vccs?) or some Zener magic (cost?) are in order here. Rev. B? ;)</p> teachop urn:uuid:4efba686-7717-e077-238b-b373c268a54d 2011-05-29T05:25:04-06:00 <p>Yes. The &ldquo;typical circuit&rdquo; in the data sheet for the H bridge has the cap minus terminal connected to the bridge common. This would have been better, if the idea was indeed a zero voltage drop reverse protection circuit (which I still suspect).</p> Ward urn:uuid:28586476-8d2e-44ff-eb25-56562b7e1ca4 2011-05-29T00:11:51-06:00 <p>41V max? Those LEDs may not like 120mA of forward current.</p> Ward urn:uuid:c1dbc9b7-a3de-c724-f51e-301e013181dd 2011-05-29T00:06:16-06:00 <p>Hard to tell. One might guess reverse polarity protection, but the only thing they&rsquo;d be protecting is U1 and U2. C2 and C5 (polarized electrolytic caps) would still be exposed to the reverse voltage and would likely fail catastrophically. Vcc undervoltage? Maybe&hellip;below 3V or so the FETs would be off. That doesn&rsquo;t really matter, though, since the FET drains (rather than the sources) are connected to ground. All that happens when the FET is off is an extra diode drop, the FET&rsquo;s body diode, is inserted between U1/2 ground and system ground. Overvoltage? I don&rsquo;t see a viable mechanism for that. Puzzling indeed. D1 is a good addition, to prevent VGS overstress when Vcc > 20V.</p> TheStig urn:uuid:4d65ab65-790e-b6ca-398f-7f07296c0209 2011-05-28T21:25:54-06:00 <p>What motors would be appropriate for using with this shield?</p> Bpaton urn:uuid:1d167eaa-96e6-4a6a-1cff-d320848312db 2011-05-28T20:21:58-06:00 <p>Why not buy one of these:<br/> http://www.pololu.com/catalog/product/707<br/> Or these:<br/> http://www.pololu.com/catalog/product/708<br/> And the more expensive VHN3 has the current sense circuit built in. Sure the form factor is not an Arduino Shield but they both cost significantly less.</p> willydlw urn:uuid:c0cc87a1-e93f-fff6-68e6-90abb7ad243f 2011-05-28T09:21:01-06:00 <p>It looks as though the voltage supplied from VCC after dropping across the 100k resistor is enough to turn on the Mosfet&rsquo;s and pull the GNDA/GNDB on the H-bridge to zero ground.</p> teachop urn:uuid:9bcc18af-af4c-0205-3b32-4c5f3a792f67 2011-05-28T05:56:01-06:00 <p>Reverse polarity protection perhaps.</p> EliTheIceMan urn:uuid:6a705136-f139-a64c-9d7d-e331477e3918 2011-05-28T01:18:24-06:00 <p>What do the two external mosfets do? Do they facilitate the under or over voltage protection?</p> Customer #66696 urn:uuid:576dc2d2-0f93-d15b-93aa-e3528a9f6773 2011-05-27T22:33:16-06:00 <p>Are the traces on the pcb large enough for 30Amps current?</p> MicroLAN urn:uuid:c34b84f1-476e-f783-647a-71282d4b0bce 2011-05-27T19:36:28-06:00 <p>They are actually C3 and C6 on the schematic&mdash;marked as DNP (Do Not Populate)</p> Quazar urn:uuid:1d71cddf-cfb3-0c0b-9839-9a68836f5bb4 2011-05-27T11:12:57-06:00 <p>It looks to me like C2 and C3 in the upper-left corner of the schematic.<br/> Large power caps to handle spikes caused by high-current motors starting.<br/> I guess you add those yourself if needed.</p> mman1506 urn:uuid:66bb46c0-497f-a4cb-dc1e-06bf9503db16 2011-05-27T11:11:46-06:00 <p>Look at the silkscreen there right under the populated ones</p> mdot urn:uuid:fa24627e-bfff-8dd0-2ed4-30f42089bb66 2011-05-27T10:18:37-06:00 <p>Why are there two unpopulated capacitor footprints?<br/> I was unable to deduce from the skee-matic.</p>