I hooked up my arduino nano to my PC via USB and I wanted to see what the ampage output would be from the 5v supply so I got my multimeter set it to the Amp setting (its one of the ones where you have to adjust the values of the amps) and put it between the 5v supply and ground. Firstly I got no reading, then the powerlight went out it made the disconnecting sound from my computer and it left a yellow mark on my breadboard and it is officially dead (it also smells bad). Why is this ? is it my multimeter or did I just do something really dumb
If you put the meter probes to 5V and ground using the AMP meter you shorted out the power supply. The probes for reading amps go IN the circuit not ACROSS the circuit. You would break the circuit somewhere, like disconnect +5V from everything, connect the plus probe to +5V and the negative probe the the circuit where +5V connected before so the meter becomes part of the circuit.
edit: check for a fuse in the meter. It may be blown and the amp function won't work until it is replaced.
did I just do something really dumb
Yes sorry.
groundfungus:
If you put the meter probes to 5V and ground using the AMP meter you shorted out the power supply. The probes for reading amps go IN the circuit not ACROSS the circuit. You would break the circuit somewhere, like disconnect +5V from everything, connect the plus probe to +5V and the negative probe the the circuit where +5V connected before so the meter becomes part of the circuit.
edit: check for a fuse in the meter. It may be blown and the amp function won't work until it is replaced.
Thanks but I don't understand fully what you have written. I have read this : http://www.allaboutcircuits.com/vol_6/chpt_2/4.html
and still not get why it created a surge. Are you saying I hooked it up the wrong way round? How did I put it in parrallel? it was in series as it went from 5v through the ammeter to ground?
An ammeter looks like a short circuit, you put a short circuit across your supply. This caused a lot of current to flow, it burnet out the fuse in your ammeter and burnt out the regulator in the arduino. How was it powered? You could have burnt out the USB supply as well although these are protected to some extent.
An ammeter should be put in seriese with a circuit so that current flows through it on the way to your device.
Not in parallel like you did.
On that web page there is a diagram that says
. Be very careful to avoid this scenario!
That is what you effectively did.
So that's what I did. Isn't that in series
So basically there has to be something in the circuit I can not put 5v to gnd. Should I get a new ammeter?
A decent meter will have the ampmeter fused. Look in the battery compartment for a fuse. Replace with the same rating fuse. See if the meter will still measure volts. Set up a test circuit with a 1K resistor and see if the ampmeter still works (should read about 5mA with 5V supply. .
I think it's fairly safe to say that most of us have done something similar at some point. The thing is that you probably won't do it again. If you do, perhaps you should reconsider having electronics as a hobby? 
dannable:
If you do, perhaps you should reconsider having electronics as a hobby?
Hell no I will I will make my GCSE in electronics worth while. I havn't done electronics for 9 years and I always enjoyed it. I thought with ardino I could get back into it as I am a programmer I thought it would allow me to make some cool stuff combining both my knowledge
In my line of work (networking), there's a saying: "If you've never taken down a network, you haven't (worked in this field) very long." This is one of those rites-of-passage type of things.
Series: (use this for amp meters, not for volt meters)
+5v >---(M)---< Arduino Vin
Gnd >---------< Arduino Gnd
Parallel: (use this for volt meters, not for amp meters)
+5v >--*--< Arduino Vin
|
(M)
|
Gnd >--*--< Arduino Gnd
wishywashy:
or did I just do something really dumb
Is the correct answer.... the ONLY time you can safely (up to the mm's fuse rating) is with low power, small solar panel, peltier, dc motors (when hand cranked), for example a 3v 20ma solar panel, you'll read 20ma with good sunlight....
otherwise you measure in SERIES, or you'll do what you did... shorted out the power supply.
For those who do not learn the circuit too complicated