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Showing content with the highest reputation on 08/14/2012 in all areas

  1. 1 point
    oPossum

    Volt/Amp/Watt meter

    This is a simple voltage and current meter that uses the TI INA219 chip. Voltage measurement range is 0 to 26 volts with 4 mV resolution and current measurement range is -4 to +4 amps with 1 mV resolution (when using a 0.01 ohm shunt). The specs are inferior to a pair of quality multimeters, but it is a fraction of the price and shows wattage in addition to voltage and current. The Nokia 5110 display is used so the firmware could be enhanced to do simple graphing. Sending the measurements to a computer could also be done. Using the INA219 makes for a very simple circuit. The normal display is three lines with voltage, amperage and wattage. Pressing the P1.3 switch will show the 6 registers in the INA219 in hex and signed decimal. The code is written in C++ and uses templates for the LCD, IIC and INA219. Software SPI and IIC is used for maximum portability. vam.zip
  2. 1 point
    PedroDaGr8

    Uni-T UT61E for ~$50

    I posted this over at fatwallet. Link Depending on if you use fatwallet or not the price is either $51.29 or $48.73 (after Fatwallet CashBack). As for the devices capabilities: [*:3uwr7ymh]Auto-Ranging! (No more setting the range) [*:3uwr7ymh]TrueRMS! (I think this is one of the better prices I have seen for a TrueRMS meter, let alone with auto-ranging) [*:3uwr7ymh]Voltage: The lowest range is 220mV highest is 750V [*:3uwr7ymh]DC Voltage: The lowest range is 220mV highest is 1000V [*:3uwr7ymh] AC Current: The lowest range is 220uA (thats micro amp I am suspicious of this) highest is 10A. [*:3uwr7ymh]DC Current: The lowest range is 220uA (thats micro amp I am suspicious of this) highest is 10A. [*:3uwr7ymh]Resistance: The lowest range appears to be 22ohm highest is 220megaohm [*:3uwr7ymh]Capacitance: The lowest range is 22nF and the highest usable range is 220uF/2.2mF (there is a 22mF to 220mF range but it is listed as reference only) [*:3uwr7ymh]Frequency: 10Hz-220Mhz [*:3uwr7ymh]Duty Cycle: 0.1%-99.9% [*:3uwr7ymh]Data Hold: 61 (points?) [*:3uwr7ymh]Diode Test [*:3uwr7ymh]Continuity Buzzer [*:3uwr7ymh]RS232 Interface (the description talks a lot about a USB interface but the image clearly shows an RS232 cable). [*:3uwr7ymh]A stand for sitting it up on a table top. [*:3uwr7ymh]Plus some other stuff. My impressions of this meter: Having owned this meter for 6months now, I absolutely love it still. It is one of the best (if not the best) meter at this price point. The quality and feel are outright outstanding (excluding the test leads). The case has a nice slightly rubberized feel but more importantly the case is THICK and rigid. I couldn't get the case to flex one bit even with all of the screws removed. The rotary dial on the front has a nice solid feel as clicks solidly into the different spots, especially the off slot which has a nice Ka-Chunk. The meter is large, I'd say its about as long as a DVD case give or take. So similar if not a bit larger than meters like Fluke, Amprobe or Extech. My meter came with both an English and a chinese manual (two seperate manuals). The leads as mentioned aren't the greatest. Mine show ~120mOhms resistance. They feel kind of cheap, though they do have a REALLY sharp tip. I can't find much at all to complain about it. It really is an amazing meter for a hobbyist. I did a test on this meters specs using some high quality KOASpeer resistors and UCC caps. The meter meets/beats all of its rated specs (which are actually quite good). EEVBlog forum like this meter as well as great for the price. Link Here is a link to the meter for $56.99 Then enter coupon code cheaper10off to knock 10% off the price. If you use the link I posted above at FW, you can use FW Cashback to get 5% back bringing the price down to the under $49. EDIT: OK now with 3 posts under my belt I can add links Hopefully, someone else finds this meter as great as I have.
  3. 1 point
    oPossum

    Volt/Amp/Watt meter

    The accuracy is +/- 0.2% typical. That is similar to a low cost 3 1/2 digit DMM. It alternates between current and voltage samples. It only has one ADC. For 12 bit resolution it takes about 1 millisecond to sample both current and voltage, so about 1000 samples per second. The resolution can be adjusted down to 9 bits for an almost 10x increase in speed. It is also possible to average up to 128 samples. Full details are in the spec sheet linked in the first post.
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