# Measuring amperes, what the reading mean?

I am new to electronics, but I don't know what the readings mean. I took measurements with a digital multimeter, the power source is a 9V battery and I have a load a LED.

Setting    Reading
20          0.05
200m        00.5
20m         0.6
2m         .600


Which setting on the A range indicates the milliamps?

I did the measurement correctly in series, on DC. The manual doesn't say, it was made in China

Here is the image of the multimeter:

• What is the load? Jan 31 '13 at 22:40
• What is the "Setting"? Is it on the A range, V range, Ohms range? AC or DC? The symbol for DC looks like a line with dots underneath. Do you have the leads plugged in to the correct sockets (COM and A) A picture will probably help. Note that shorting the battery (which the multimeter essentially does on current range if directly across the battery) for longer than a second or two is not a good idea - make sure the multimeter is in series with the load. Jan 31 '13 at 22:42
• Show the circuit of how exactly you connected all the components, including the meter. Also, how is this not directly described in the meter manual? Jan 31 '13 at 22:48
• The multimeter was made in China, the manual just says where to place the wires. I measured correctly Jan 31 '13 at 22:55
• If you know you measured correctly, why ask the question? The photo shows a multimeter set to 200mVDC, and with no leads attached. We still don't know how you set your multimeter up or what exact load you used (which LED? did you use a resistor to limit current?), so have no way of confirming your readings are correct. Feb 1 '13 at 0:07

## 1 Answer

All of the settings with "m" in them represent milliamps. The "setting" is what we call the range, or the "full scale value". It indicates the highest value that can be read without being "out of range". The reason the readings look different is that the precision changes. Specifically, .600ma is the same as 0.6ma. It's also the same as the 0.5 reading (shown as "00.5") but you'll notice it is "off by one count". This is what happens when you measure something that is a tiny fraction of the full-scale value. The accuracy of the measurement suffers. And that's why you should choose a range that is comparable to what you're measuring.

The remaining measurement was done on the "20" scale, which is 20 Amps. You got a reading of 0.05 A there, which would be 50mA, but that's just too far "down in the noise" to be useful.