How to measure mA

My multimeter doesnt have mA, or i dont know how to use it

It wouldn't be a "multi"-meter if it didn't. Maybe post a photo or a link to one so we can tell you what to set it to.

Put a 1ohm resistor in series with the circuit, measure the voltage drop across it in mV....the reading you get is the same as mA.

But as as BB says, it would be a rare mm that cannot do mA....

Regards rog8811

Heres my multimeter

Your photo is not very clear but if you look at the right side of your dial it
says DCA. That is your Amp Meter scale. Choose the 200m scale and you can
measure up to but not exceeding 200ma.
It looks like that is the highest milliamps that your meter will measure.
Your RED lead is already correctly plugged into the MADC socket.
Hope this help.

crap i need to measure up to 500mA to test my driver :-/
is there a way to test it with this, like measuring each batteries mA then adding it up
i'm putting 4 AA's into this driver:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612

The other solution is to put a 1 ohm resistor in series with your circuit
under test and measure the Voltage in millivolts. (1mv = 1ma).
Place your meter on DCV scale on the left hand side of the scale and choose
2000m. That is the 2000mv scale. Now with the meter set up like that and
a 1 Ohm resistor in series with your circuit place the meter's probes on each
side of the 1 Ohm resistor and you can read up to 2000mv or 2000ma.

I said.....

Put a 1ohm resistor in series with the circuit, measure the voltage drop across it in mV....the reading you get is the same as mA.

Click to expand...

laserbee said......

The other solution is to put a 1 ohm resistor in series with your circuit
under test and measure the Voltage in millivolts. (1mv = 1ma).

Click to expand...

Regards rog8811

The picture is blurred but also HUGE. Meters going over 200 mA also have a plug in for a 10 or 20 amp range. I don't see one on yours.

Use the resistor ---

Mike

rog8811 said:

I said.....

Put a 1ohm resistor in series with the circuit, measure the voltage drop across it in mV....the reading you get is the same as mA.

Click to expand...

laserbee said......

The other solution is to put a 1 ohm resistor in series with your circuit
under test and measure the Voltage in millivolts. (1mv = 1ma).

Click to expand...

Regards rog8811

Click to expand...

Well... what are you going to do.... if you are a non believer ;D ;D ;D

Seeing as we are on the subject.. Is there any way to mod a DMM that only measures up to 400ma, to measure at least up to 5 or 600ma? I asked IgorT about this one, as I was going to try a resistor in line with the lead to the meter, but he said its not a reliable method. So what can I change out in the meter to raise the value? (if possible)

So much resolution... so little detail.

As for modding a meter, you might be better off just buying one that has the capability. The multimeters use an ADC to determine the value of the amperage flowing through the multimeter. I believe the switches simply switch the meter to lower parallel resistance values to allow for less current to flow and be measured by the ADC. It might be hard to increase the accuracy of the meter without actually introducing more resistance in the ADC current path, which is just about the same thing as measuring the resistor using the voltmeter.

Also, many don't support higher amperages because that's a lot of juice flowing through that meter and they need protection for it. My old meter's fuse blew out from too many amps. The ExTech I use requires me to switch to a different measurement plug hole (on the meter) to go up to 20A; the regular one only goes up to 400mA fused. They probably have separate holes for accuracy reasons, not so much for the fusing.

Since rkcstar isn't making drivers, etc. anymore, you can construct your own test load that may fare better than just a single resistor, by putting a large 1 ohm resistor in series with 3-4 rectifying diodes. Then you measure across the resistor for your mA value.

Good lord why can't people take in focus digital pics. It's digital for pete's sake, there's no wasting of film.

Maybe my problem here , BUT why are all the pictures so HUGE ??
I have to scroll and scan everything anymore. I'm done with that.

Mike

Yeah... I'm amazed at even in my job where photographic evidence is key... how many pictures get screwed up. That's why I love my picture resizer for in-browser use Get's the pics to atleast a decent, usable size without having it open it up in a new window...

And rog, you have to take in to account that while you *said* the same thing... you might have used terminology that not everyone necessarily knows. Honestly I was gonna have to look up what exactly you were talking about when you were talking about measuring the drop in voltage across it... I'm still a noob, but that's why I read up on this stuff

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92020
^^^^That's the multimeter that I have now... but I'm sure that I'll probably need to upgrade it eventually

ArdvarkOfDoom,
  there is nothing wrong with that inexpensive mutimeter.
One just need to know how to use it correctly.
It is the type we suggest for our inexpensive LPM modules.

It's a lot better than wetting your fingers with spit and touching a circuit
to find its voltage or curent.  LOL ;D ;D ;D ;D ;D