edit typo

I have corrected "amperage" to "current" (see raspberrypi#242)

Author: LornaLynch

setup/README.md

@@ -17,7 +17,7 @@ A guide to setting up your Raspberry Pi
 - [Power supply](../hardware/raspberrypi/power/README.md)
     - The Pi is powered by a USB Micro power supply (like most standard mobile phone chargers).
     - You'll need a good-quality power supply that can supply at least 700mA at 5V.
-    - Low amperage (~700mA) power supplies will work for basic usage, but are likely to cause the Pi to reboot if it draws too much power.
+    - Low current (~700mA) power supplies will work for basic usage, but are likely to cause the Pi to reboot if it draws too much power.
 
 ### Optional