SparkFun Electronics will be closed on July 3rd, 2015 in observance of Independence Day. Any orders placed after 2:00pm MT on July 2nd will be shipped out after the weekend. Thanks!


Member Since: December 2, 2009

Country: United States

  • According to the Datasheet, time to first lock is 38 seconds from cold start, or 3 seconds hot-start. The figure quoted on this page (3 seconds from cold) is currently impossible, with the required data only being sent from the GPS satellites once every 30 seconds or so.
    Also, to save you time, this is a 1Hz unit.

  • Re. Static Electricity: The primary reason we don’t die from static, as I understand it, is that the body’s capacitance is tiny. About 100pF or so. There’s no limitation anywhere causing the current or power to be low, since humans are primarily a capacitive source. The current and power are huge, but only for a fraction of a second, and only a tiny amount of energy can be dissipated (since only a tiny amount was stored).
    Also, what does “total power” mean? Average, peak, integral .dT?

  • I’m sure that the answer to “Charging Billy’s Battery” is not 10 hours. If that were true, it’d be 100% efficient. As well as that, only really crap chargers (which you don’t want) are constant current all the way. Better ones use constant voltage at the end, when cell voltage is at the maximum acceptable level (normally 4.2V). 11 hours is the closest answer, but I’d say 12 or more to be sure.
    While we’re at it, good luck getting the AAs in “Billy’s Battery Capacity I” to drive RGB leds. Remember that battery capacity for alkalines is typically quoted down to 1.0 or even 0.8V. To make use of all of the capacity, you’d need a blue LED running on

  • Be extra careful if you’re soldering to the back of these. The inner wire is attached to a sputtered layer, which is solder soluble (in my experience). This means that excessive soldering reduces electrode area, and the sound output is reduced proportionally. If you’re aware of this, and don’t spend forever soldering it (I was using it for a ground plane on a tiny alarm clock), you should be fine.

  • “Thermal mass” is the wrong term. “Radiative (or dissipative) area” is much better. Using a near-ideal large thermal mass (e.g., a thermos full of water) for a heat sink will result in a device which takes a very long time to overheat, but will still do so regardless of the size of the thermal mass. A dissipative or radiative area provides the capacity to get rid of heat to the environment, rather than store it.

  • Spelling error in the title; should be “barrel”, not “barrek”. These (and their mate) should save me heaps of time prototyping power supplies!

  • Given that these have +- 0.5% stability, where crystals have 50ppm (+-0.005%) stability, I am not so sure that these “stick closer to their specified frequency”.

No public wish lists :(