Raspi.tv used their emeter to compare power usage on the Pi model B and B+.
The power circuit on the new Raspberry Pi B+ has been completely redesigned. It now has an efficient switching regulator. So I decided to take my trusty emeter, a tool I spent far too much money on a few years ago whilst in the grip of the aero-modelling ‘bug’, and make some measurements.
I measured the current and voltage going into the Raspberry Pi. The emeter has a calibrated shunt (small blue rectange in the photo with ‘battery’ and ‘load’ at each end) that’s good for up to 20 Amps. This is a way of measuring without disturbing the circuit. (It measures the voltage drop across a fairly low-value resistor.)
I did these measurements on both a late rev 2 model B and the new B+. Both were measured with just a wireless keyboard dongle AND with both keyboard dongle and Edimax wifi dongle (which uses an additional 40-50 mA).
The results are in the video, which also shows hot-swapping a wifi dongle without the Pi rebooting…
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