Differences

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--- current_measurement [2024/07/26 21:52] – river
+++ current_measurement [2025/04/27 20:17] (current) – river
@@ Line 3: / Line 3: @@
 ===== Nordic Power Profiler Kit II =====
-[[https://infocenter.nordicsemi.com/pdf/PPK2_User_Guide_v1.0.1.pdf|Manual]]
+{{ :ppk2_user_guide_v1.0.1.pdf | Manual}}
 == Limits ==
@@ Line 12: / Line 12: @@
 == Accuracy ==
+Specified:
   * < 50mA: ± 10% and ± 2% offset
   * >= 50mA: ± 15% offset ± 5%
+At points I checked, it was within 1.5%.
 == Qs ==
@@ Line 20: / Line 24: @@
   * Is it robust to output overcurrent or overvoltage?
   * What does LED mean?
+== Usage ==
+In ammeter mode, it requires a ground connection. Only connecting power in and out will cause weird / oscillating or maybe just slightly wrong readings.
+It also needs enough voltage to give a proper reading. Low voltage from the input to ground can cause readings that are a bit off.
+USB is not isolated. Ground is shared with power output / target device.
 == Log ==
@@ Line 26: / Line 38: @@
 I connected it to a faulty device which drew too much current. The ppk2 firmware crashed as soon as power was switched on, and the device disconnected from USB. It seems like it does not have any overcurrent protection. A forum post said the sense resistors were damaged by overcurrent, and another suggested that they could be partly damaged and ruin the accuracy. Can it be recalibrated?
+April 2025
+Checked readings against good multimeters. It seems it is still in spec. Within about 1.5% for values I checked.
 == Misc ==