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…
Each Friday is PiDay here at Adafruit! Be sure to check out our posts, tutorials and new Raspberry Pi related products. Adafruit has the largest and best selection of Raspberry Pi accessories and all the code & tutorials to get you up and running in no time!