Using the multimeter with arduino !

Hello everyone,
I built a circuit with arduino Nano. Circuit seems not working as it supposed to, so i got my cheap multimeter (the yellow rectangular one) and i tried to measure the voltage to see if there is any on some pins. When i connect the multimeter to the + and - in the circuit, the arduino turns off and no value is being detected. Same happens when i connect Vin and Gnd on the 4021 Shift In IC so I need your help knowing what is going on please ?

Have you checked that the multimeter leads are in the correct sockets?
Your problem sounds like the leads are set up for a high current range, say 10amps.
I destroyed an mcu chip and also achieved a bright blue mains powered flash in a similar way

6v6gt:
Have you checked that the multimeter leads are in the correct sockets?
Your problem sounds like the leads are set up for a high current range, say 10amps.
I destroyed an mcu chip and also achieved a bright blue mains powered flash in a similar way

yes the black is in com, and the red in 10A. It seems something is broken in my multimeter because i tried another one and it worked perfect. But what might be broken in my MM ? a fuse maybe ? because it is simply short circuiting when i connect it to wires

Putting the multimeter leads in the 10 Amp sockets effectively puts a near short circuit across the leads. Look up Ammeter shunt resistor. That is how a delicate little meter can measure massive currents.

To measure current, you always put the meter in series with the load.

Hi.

As hinted by 6v6gt, connecting a multimeter the wrong way can be dangerous to very dangerous, even to yourself.
Don’t do that, and expect to have damaged something if you already did.
For the measurement you want to do, the wires don’t go where you have them now.

Look at this picture, it has the wires to the correct positions for your measurement:

Compare it to your multimeter, it should have similar descriptions next to the connectors.
The range selector (knob) should be in the V- section, and if it has any, the next higher range than you want to measure (which would be 20 volts in most cases as it is with this example).

MAS3:
Hi.

As hinted by 6v6gt, connecting a multimeter the wrong way can be dangerous to very dangerous, even to yourself.
Don't do that, and expect to have damaged something if you already did.
For the measurement you want to do, the wires don't go where you have them now.

Look at this picture, it has the wires to the correct positions for your measurement:

Compare it to your multimeter, it should have similar descriptions next to the connectors.
The range selector (knob) should be in the V- section, and if it has any, the next higher range than you want to measure (which would be 20 volts in most cases as it is with this example).

thanks for your reply MAS3
well at the moment yes i have this setup and i am measuring Voltage with 20V selected but seems that my other multimeter has something broken but what might be ? the multimeter i am using now is giving me the right values i need

MAS3:
Look at this picture, it has the wires to the correct positions for your measurement:

There is something seriously wrong with that picture - as has been posted before. :astonished: Do you know what it is?

I do.

But so is the source of the google result for some picture that shows what i wanted it to show.
Didn't want to download, edit and upload it to the forum, so this had to do.

But what might be broken in my MM? a fuse maybe?

If you have connected your MM with the connections to A and used it as described then you might well have blown the internal fuse. Make sure the MM is connected for V as others have described. You might have to open the case to replace the fuse, depends on the design of the MM.

The 10 A shunt is a large lump of wire - not a fuse. If you connected it across any usual sort of Arduino power supply, the lump of wire would have won hands down.

PerryBebbington:
If you have connected your MM with the connections to A and used it as described then you might well have blown the internal fuse. Make sure the MM is connected for V as others have described. You might have to open the case to replace the fuse, depends on the design of the MM.

It seems the fuse is soldered :confused:

Paul__B:
The 10 A shunt is a large lump of wire - not a fuse. If you connected it across any usual sort of Arduino power supply, the lump of wire would have won hands down.

what do you mean ?

firashelou:
what do you mean ?

That "lump of wire" shunt has NO problem with the current a typical Arduino power supply can deliver, after all it's meant to measure currents of up to 10A. So if you connect that between the + and - of a power supply, you effectively short it, and if something breaks it'll be the power supply.

  • or whatever (Arduino) output port you were attempting to measure on.

ok thanks everyone for the help i really appreciate it :slight_smile: