Member Since: January 7, 2010

Country: United States

  • "Check the datasheet for the MOSFET below for full specifications on how much current this board can handle."
    Really? The datasheet says each transistor can support continuous load of 30 A. However, the previous version of this product was (according to its comment log) limitted to ~8 A per transistor by the board traces. Have they been massively increased in cross-section in this revision?
    Also, the best guess I can make for the screw terminals (link from a related item that has a part list) is that the terminals are rated for 6 A.
    It's the lowest component current rating of the entire circuit that sets the circuit's rating. If my inferences are correct, the instruction to get the current rating from the datasheet gives one a factor of five error.

  • Is it just me, or are some of the new products (for example, BNC connector, soldering iron) not showing up for other people when you click the "New Products" button at the top of the left column of this page?
    I can, FWIW, get to the catalog pages for the new parts, they just aren't showing up in the "New Products" list.
    I don't know if it's relevant, but last week, things on that page appeared to be in an order other than most recent item first, despite the sort order being "Date Added." ATM, my view of the list shows the first few items as Arduino Fio, AVC poster and AVC t-shirts.

  • SparkFun,
    When you have a couple of minutes, you should fix the description on the nylon locknuts page. It says, in part, "A nylon nut can save you the hassle of shorting out the ground plane on a PCB without enough spacing around the mounting hole.". That's a true statement, but it doesn't apply to the locknuts with nylon inserts. The nuts described in the new product post above and shown on that page are metal nuts with a nylon insert that reduces the likelihood that the nuts will vibrate loose. However, the male thread (bolt or stud) engages with the female metal thread of these nuts, so there's a conductive path from the male thread to the surface on which the body of the nuts rests.
    The described electrical isolation can be obtained by using nylon nuts, which SparkFun does offer. Unfortunately, it appears that someone copied the text for the nylon nuts and pasted it in for the metal nuts with nylon inserts. The page for the single-piece nylon-insert metal nuts has copy that reasonably describes those parts.
    Electrical isolation can also be obtained by using nylon bolts with the nylon-insert metal nuts, but the isolation in that arrangement is a function of the bolts, not the nuts.
    While I'm writing, I second the request for nylon bolts. If you don't want to stock an assortment of lengths, just stock long ones. Nylon bolts are pretty easy to cut to length.

  • Sparkfun,
    Darn, I missed by one day. ;o{ I predicted you'd start talking about Maker Faire tomorrow. Had I considered that the weekly new product posts are Fridays, I wouldn't have done that.
    FWLIW, I'll be there for the duration with Playing At Learning, the Northern California FIRST partner. We're staging an off-season FIRST Tech Challenge (FTC) robotics tournament. We'll also have a FIRST Lego League (FLL) table set up.
    I invite all members of the SparkFun community (personnel and customers) to drop by and see how much fun robots that are not trying to kill each other can be.

  • What's the basis of the "Resistor Value 390 Ω"?
    At the rated maximum current of 20 mA, 390 Ω will drop:
    V = I * R = 20 mA * 390 Ω = 7.8 V
    That's more than a 4-pack of alkaline, NiCd, or NiMH cells provides to an open circuit.
    At the nominal 6 V from a 4-pack of alkaline cells:
    Vres = Vbatt - Vled = 6 V - 1.5 V = 4.5 V, so
    I = Vres / R = 4.5 V / 390 Ω = 11.5 mA
    At the nominal 4.8 V from a 4-pack of NiCd or NiMH cells:
    Vres = Vbatt - Vled = 4.8 V - 1.5 V = 3.3 V, so
    I = Vres / R = 3.3 V / 390 Ω = 8.5 mA

  • Is this a "MonoMatrix" product or a "MondoMatrix" product?

  • @SparkFun:
    It appears your charitable donation total was $7,012 short of the cap you set on it.
    How about letting those of us who missed the opportunity (I, for example, was in transit to the other side of the globe on business.) play the quiz just for charity? Why not give us a week (or less, if we hit the cap) to play, one attempt of up to 10 questions per account, for $3/correct answer to charity.
    That way, folks who really do want to try the quiz (that is, are willing to answer quiz questions without the chance of personal monetary gain) will have a chance to do so and SparkFun can do a bit more social good.

  • One serious gap:
    What's "the appropriate voltage" and what current is drawn at that voltage?
    Two picky things:
    1) Is this wire "flourescent" (emitting ground grain) or "fluorescent"?
    2) Has the meter shrunk or the foot expanded? The last time I checked, 3 m was a bit short of 10 feet.

  • @SparkFun,
    It would be helpful if you told us the maximum wire size for the terminals or, at least, which terminals those are so we can go find that datum.

  • rsp,
    Am I missing something here? It appears this kit has a 10K pull-down on the gate.
    Are you suggesting that:
    a) If one uses this kit, an additional high impedance path to ground from the gate is necessary or
    b) If one uses a MOSFET for this purpose without using this kit, one needs such a pull-down for the gate?

No public wish lists :(