I came across a shop which had some clamp meters on sale.
Knowing knowing nothing about them, I passed.
Later checking the prices online, they originally were pretty expensive.
My question: can a good clamp meter be a replacement for a normal DMM?
The ones on sale were from the Graphtec CM series.
Can’t remember them exactly, but I guess they were the CM-207,208 an 209
Could they be used for checking Amperege on flashlights?
See post #18
That depends on what you want to measure. Clamp meters are very good when measuring higher currents, but cannot be use at low currents (Except some special and very expensive models). Also be careful with AC/DC ranges, not all clamp meters can measure A DC.
A clamp meter with a 400A range and a 1%+3 precision would show a 1A current somewhere between 0.69 and 1.31A, with a 40A range it would be much better.
Thanks PilotPTK and HKJ for the answers.
These Graphtec come, as far as I know, including test leads.
So I was just curious if this would be more precise than my $8 ebay DMM.
PilotPTK: How can you use the clamp-meter to measure A on flashlights? (without using the test leads)
WHAAA! interesting! Thanks!
1.Does your clamp meter give an accurate reading this way?
2.Is there a difference between this way of reading and with test leads?
Just curious, because I hope to go back to that shop, and if they still have them for dirt cheap, I might pick one up.
I have a Benning CM2 that i bought for work. It is designed to work from 10mA upto 300A. You measure voltage with its test leads, and current with the clamp.
I tested a few different cells in my Trustfire Mini-01 today, but i had to run a cable off each end of the battery to the flashlight head, then clamp the meter round one of the cables to read the current.
As accurate as it can, with a 40A range it is acceptable to measure a couple of amperes.
There is somtimes a very significant different, due to the resistance in test leads and the burden voltage in a meter. When measuring a couple of amperes and above the clamp meter is often the most precise way to measure the current when working with a few volts.
Thanks… I might grab one if they still have them on sale!
Looks like they are quite accurate then! maybe more accurate than my current DMM
When the have the correct range, they have a acceptable accuracy, but a DMM usual has much better accuracy.
With flashlights the trouble is low voltage, losing 0.1 to 0.6 volt in the meter will significantly affect the result. Using a clamp meter, you can easily get around that voltage drop (Using a thick wire), and you only error is due to the meter.
For flashlight usage I will strongly recommend you get a clamp meter with a 20/30/40A range (i.e. a resolution of 0.01A) and not only a 200A or larger range.
Hi HKJ,
ok, gotcha!
pity, because the Graphtec`s are 400A only… I think.
But they were pretty cheap, so I`m still thinking of buying one if they are still there. They were only about 20-30 bucks .Retail price is about 250.
Have a look at this before you buy. http://www.graphtecdataloggers.co.uk/fileadmin/gtadmin/Handheld/e-measuring_catalog_E\_\_low.pdf
The CM 205/207 are AC only.
The CM208 and upwards are AC/DC.
Thanks for pointing that out… Was thinking about the CM208 or 209 then.
No problem. Worth trying a 208/209 if you can get one at a good price.
Got the cm-209.
Got a higher reading with the clamp meter than with my cheap DMM.
My Solarforce with XML gave 2.6A with the clamp meter and 2.4 with DMM.
The thing I don’t understand is that I could measure the A with connecting the test leads on the clamp meter. The light just didn’t turn on unlike connecting it to my DMM!?
What did I do wrong?
