Electronic Projects, forums and more.

Go Back   Electronic Circuits Projects Diagrams Free > Electronics Forums > General Electronics Chat


General Electronics Chat This forum is for general chat about electronics, eg: Dont know what a part does? Dont know how to read a circuit? Want to get an opinion?

Reply
 
Tools
Old 1st July 2009, 07:37 AM   #1
Default Multimeter question.

I have just bought a bunch of stuff to get into making circuits and was playing around with the multimeter, to get used to how it works. I tested a 9v battery fine (came up with 9.6v) but when I tried to do amps nothing came up, regardless of what setting I had it on. Am I doing something wrong?
rippa32 is offline  
Old 1st July 2009, 08:08 AM   #2
Default

Quote:
Originally Posted by rippa32 View Post
I have just bought a bunch of stuff to get into making circuits and was playing around with the multimeter, to get used to how it works. I tested a 9v battery fine (came up with 9.6v) but when I tried to do amps nothing came up, regardless of what setting I had it on. Am I doing something wrong?
On some multimeters, the +test lead plugs into a different hole in order to measure amps.

Also if you have tried to measure amps by connecting the meter across a 9V battery, you could have blown the internal protection fuse.!!
__________________
Eric " Good enough is Perfect "
I will NOT answer PM's requesting technical help, please use the Forum
PIC tutorials: Nigel's www.winpicprog.co.uk/ Bill's: www.blueroomelectronics.com/
ericgibbs is offline  
Old 1st July 2009, 09:25 AM   #3
Default

What do you mean across?

Also I don't think I have blown a fuse as everything else still works fine.

Last edited by rippa32; 1st July 2009 at 09:27 AM.
rippa32 is offline  
Old 1st July 2009, 10:56 AM   #4
Default

Quote:
Originally Posted by rippa32 View Post
What do you mean across?

Also I don't think I have blown a fuse as everything else still works fine.
The fuse would only affect the current ranges - how did you connect the meter when trying the current ranges?.
__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk
Nigel Goodwin is online now  
Old 1st July 2009, 10:57 AM   #5
Default

Same as I did for voltage.
rippa32 is offline  
Old 1st July 2009, 10:58 AM   #6
Default

Quote:
Originally Posted by rippa32 View Post
Same as I did for voltage.
That was 'across' the battery then - and if the battery can supply enough current, it would have blown the fuse.
__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk
Nigel Goodwin is online now  
Old 1st July 2009, 10:59 AM   #7
Default

Would a 9v battery supply that much current? Ugh, it never actually explained this in the manual I got with the multimeter.

EDIT: I just re-read the manual and it actually says to "Connect the test leads accross the source or load under measurement."

Last edited by rippa32; 1st July 2009 at 11:03 AM.
rippa32 is offline  
Old 1st July 2009, 11:04 AM   #8
Default

Quote:
Originally Posted by rippa32 View Post
Would a 9v battery supply that much current? Ugh, it never actually explained this in the manual I got with the multimeter.
Meters don't come with a five year electronics course, you're supposed to know what you're doing?.

As for the amount of current, it depends on the battery type - a NiCd one can supply a LOT of current.
__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk
Nigel Goodwin is online now  
Old 1st July 2009, 11:04 AM   #9
Default

Quote:
Originally Posted by Nigel Goodwin View Post
Meters don't come with a five year electronics course, you're supposed to know what you're doing?.

As for the amount of current, it depends on the battery type - a NiCd one can supply a LOT of current.
It's just alkaline. Oh and the fuse on the multimeter is .2A if that helps.

Last edited by rippa32; 1st July 2009 at 11:10 AM.
rippa32 is offline  
Old 1st July 2009, 01:46 PM   #10
Default

The fuse has blown. Just get a thin strand of wire from a piece of hook-up flex and solder is across the ends of the fuse.

Last edited by colin55; 1st July 2009 at 01:47 PM.
colin55 is offline  
Old 1st July 2009, 01:52 PM   #11
Default

I'll probably just replace the fuse. Would I have damaged anything else?
rippa32 is offline  
Old 1st July 2009, 02:56 PM   #12
Default

Quote:
Originally Posted by rippa32 View Post
I'll probably just replace the fuse. Would I have damaged anything else?
If the original fuse was the correct rating, the meter should be OK.

Use the correct type of fuse.!!
__________________
Eric " Good enough is Perfect "
I will NOT answer PM's requesting technical help, please use the Forum
PIC tutorials: Nigel's www.winpicprog.co.uk/ Bill's: www.blueroomelectronics.com/
ericgibbs is offline  
Old 1st July 2009, 02:59 PM   #13
Default

Yeah, the fuse was what came with it, so I assume its the right one. Everything else seems to work fine too. Also I know which one to get too. Thanks for the help.
rippa32 is offline  
Old 1st July 2009, 03:36 PM   #14
Default

Hi Rippa,

before you experience severe trouble with your multimeter take a look at the attached circuit which is drawn in three possible conditions.

It's quite easy to see that Ohm's law is one of the most important when dealing with electricity.

Assuming an inner resistance of almost zero Ω a shorted 9V-battery (also shorted by an ammeter) might deliver a current of 900A at a resistance of 0.01Ω of the ammeter (theoretically).

Voltmeters are correctly wired across the load resistance to measure the true voltage drop (without losses within the cable), while ammeters are connected in series with the load resistor. Their resistance must be as low as possible to avoid any additional voltage drop because of resulting erroneous voltage drop readings across the load.

If you happen to connect your multimeter parallel to a supply source using the 10 or 20A range you might prepare to purchase a new one. (The fuse is only used for the 200mA range in most DMMs.)

Boncuk
Attached Thumbnails
Multimeter question.-s1-s2-off.gif   Multimeter question.-s1on-s2off.gif   Multimeter question.-s1-s2-.gif  
__________________
Proper Planning Prevents Piss Poor Performance

Last edited by Boncuk; 1st July 2009 at 03:41 PM.
Boncuk is offline  
Old 1st July 2009, 03:40 PM   #15
Default

Quote:
Originally Posted by colin55 View Post
The fuse has blown. Just get a thin strand of wire from a piece of hook-up flex and solder is across the ends of the fuse.
That's a well known Turkish and Thai way to repair fuses.
__________________
Proper Planning Prevents Piss Poor Performance
Boncuk is offline  
Reply

Tags
multimeter, question

Thread Tools
Display Modes


Similar
Title Starter Forum Replies Latest
multimeter shermaine General Electronics Chat 4 28th September 2008 08:12 AM
Multimeter Question matthewwren General Electronics Chat 13 29th January 2008 08:01 PM
Multimeter irisd General Electronics Chat 7 7th November 2007 01:12 PM
Multimeter Question raphaelriv General Electronics Chat 15 6th July 2007 05:11 PM
LED multipack / multimeter question daviddoria General Electronics Chat 6 15th February 2003 11:39 AM



All times are GMT. The time now is 09:07 PM.


Electronic Circuits  |  Learning Electronics
eXTReMe Tracker