Originally Posted by Greg Lovern
But I tried checking the current too (should be 2A), and it seems to bounce around rapidly ybetween 0 and about 1.2A, and everything inbetween. I don't know much about this kind of testing though. I carefully followed the multi-meter's instructions but I could have done something wrong. Does it sound normal for the current to cycle around like that?
I tested the current for the wall wart for a baby monitor, and the reading was steady.
Not knowing how you "tested the current", it's hard to say. You can't accurately measure the current without a load (the power supply hooked up to the device it powers).
Even with that, you have to measure current "in series". If you don't know what that means, then you aren't going to accurately measure current with a multi-meter.
Without a load, it would make sense that the current reading fluctuates (there's not a constant demand for power).
It also depends on whether the wall wart outputs AC or DC voltage (if you have a digital multi-meter it should indicate which).
As far as the current rating, it is only listed as to what that power supply is capable of providing.
If your device requires 2 amps, then you don't want to use a substitute power supply that only outputs 1 amp (made up numbers).
For testing purposes, you could use a wall wart with a higher current rating as long as the voltage is the same.
The expander will only use the current it needs to operate.