The DrDAQ is fed by the + 5V (nominal) of the USB interconnection with the companion PC.
Strangely enough (I may be mistaken by oversight) Pico Technology does not specify anywhere what is the current consumption of the device. Here below I give typical measurement data taken on my own DrDAQ.
USB voltage.............................5.1V (depends on the PC used and can be anywhere between 4.75 and 5.25 V).
DrDAQ connected to PC................50.2 mA - no software switched on, just "dead weight".
DrDAQ with Picolog operative.........48.5 mA - all available channels switched on & digital outputs @ "0" V.
DrDAQ with Picoscope operative......53-54 mA - all available channels switched on + signal generator @ 1 Khz/1.5 Vout.
No measurement wad done wil the multi-color LED ON, as this feature looks more like a demonstration device.
The buffer (see posts) takes an additional 5 mA.
To conclude the DrDAQ draws very little current, compared to the 500 mA spec of most USB outputs and, even with the additional buffer, current on the USB busbar never exceeds 60 mA.
QUESTION: What happens if the USB supply within the PC fails and outputs 10V or more? Is there any supply input protection within the DrDAQ?