Using a Multi-Meter as Amp-Meter

[sludgeguts]

Surely though, if you are measuring the ampage of a set of LEDs running off a 12v DC supply (on the Maplins meter, for example) you would have the black lead in COM, the red lead in the socket above this (poss labelled V, Ohm, mA) and the main dial set to read off the highest setting for DCA? rather than having the red lead in the 10A socket?
then connect the meter in series with the LEDs.

 

[sledge]

The meter itself is affecting the circuit. Because it needs to be connected in series you need one with a very low impedence to take accurate current readings. Yours would appear to be too high for that particular application and is in effect causing an open circuit.

MMs need a low impedence (or ohms per volt rating) to measure current accurately and a high impedence to measure voltage accurately. Ever wondered why ones from Maplin cost £5 and `professional` ones made by companies like AVO Megger and Fluke cost several hundred??......well this is part of the answer

 

[Ziggy122]

The meter itself is affecting the circuit. Because it needs to be connected in series you need one with a very low impedence to take accurate current readings. Yours would appear to be too high for that particular application and is in effect causing an open circuit.

MMs need a low impedence (or ohms per volt rating) to measure current accurately and a high impedence to measure voltage accurately. Ever wondered why ones from Maplin cost £5 and `professional` ones made by companies like AVO Megger and Fluke cost several hundred??......well this is part of the answer

It was a cheapie thing as it was important when it came to Doing My Rc work
where its all Voltages and not much more i'm affraid

It was just good when i had to for working on the punto - its cheap and cheerful and at end of day if it broke i'd spend a-little more next time

Ziggy

 

[bladecs_04]

if you connect the circuit up correctly take one wire off put your meter in series if the leds dont come on then the meter is open circuit. the meter should act as a solid wire. if the leds do come on but the meter still isnt picking anything up then i would say the meter isnt sensitive enough

 

[craigb244]

I use one of them crappy £5 meters for non accurate stuff and it will work for what you are doing (even tho it shows up to 10amp it will show up to iirc .10)

you say that when you connect them to the meter they dont light up?
First of all are you connecting it in series? this means for example... cut the live feed and connect one wire of the meter to one side of the cut wire and the other meter wire to the other side of the cut wire (wont matter which way around as the meter will just show -and the draw)

if your connecting it in parallel then you will be shorting the supply out with the meter (chances are the supply will have some overload protection and as you say its only 1.5amp it wont blow the fuse(altho it should show a reading as current will be flowing through the meter))

second... are you connecting the meter up right?
the COM/black wire always stays in the COM/black terminal
but the red lead needs to be switch to the "amp" terminal to read amps. (top terminal on the maplins meter in the link)