good inexpensive DC clamp ammeter?

[mathog]

This is a bit off topic, since the intended use is in a car, but can anybody recommend a good inexpensive DC clamp ammeter? Assuming such a thing actually exists, which after some preliminary research, is looking a bit doubtful. 2-3% accuracy on currents down to about 0.5A at 12V would be acceptable.

[Chriso]

Originally Posted by mathog

This is a bit off topic, since the intended use is in a car, but can anybody recommend a good inexpensive DC clamp ammeter? Assuming such a thing actually exists, which after some preliminary research, is looking a bit doubtful. 2-3% accuracy on currents down to about 0.5A at 12V would be acceptable.

I'm just about to buy http://cpc.farnell.com/1/1/34229-cla...226-tenma.html

[mathog]

Originally Posted by Chriso

I'm just about to buy http://cpc.farnell.com/1/1/34229-cla...226-tenma.html

Please check the DC current performance when you get it and let us know how it does. Especially check the stability of the DC ampere reading when the clamp is repositioned (not reclamped, just reoriented on the wire).

Thanks.

[Toasty]

Sears has one. $60 - http://www.sears.com/shc/s/p_10153_12605_03482369000P

Sears Item# 03482369000 | Model# 82369

DC clamp meters are not common. Most are AC.

[mathog]

Originally Posted by Toasty

Sears has one. $60 - http://www.sears.com/shc/s/p_10153_12605_03482369000P

Google will turn up a fair number of cheap DC clamp on ammeters. The problem is knowing before purchasing which, if any of them, will work reliably.

[Toasty]

>>Google will turn up a fair number of cheap DC clamp on ammeters.<<
Please show me 3.

>>The problem is knowing before purchasing which, if any of them, will work reliably.<<
Ya spends yer nickel and ya takes yer chances...

[PlainBill]

Actually, an AC clamp on ammeter is pretty simple in design, and not that expensive to manufacturer. I'm not sure about a DC clamp on ammeter. There are no oscillating magnetic flux lines to use.

PlainBill

[mathog]

Originally Posted by Toasty

>>Google will turn up a fair number of cheap DC clamp on ammeters.<<
Please show me 3.

More than 3, sorted by ascending price. The trick is figuring out which of these are really DC clamp ammeters.

http://www.amazon.com/s/qid=12803597...240&sort=price

Originally Posted by Toasty

>>The problem is knowing before purchasing which, if any of them, will work reliably.<<
Ya spends yer nickel and ya takes yer chances...

Actually it would be nice to just spend the one nickel...

[Toasty]

Nice sorting... $16.49, $86.83, $49.95...

Anyway:
1 - 5: No. AC current only
6: Yes. $163 & starts at 400A, so NO.
7: Yes-maybe. Range to 600A but no clear specs.
*Now past the Sears model in price*
8: Yes. Range to 400A
9: No. AC current only
10: Yes. Range to 600A
11: Yes. 200A and 0.1A resolution. $80 & free ship

Basic problem with them is the range is too broad. Measuring low current may not be accurate enough. The Sears unit breaks it into 2 ranges, 40A & 400A. Set to the lower scale, you would be closer than these other units which auto-range up to 600A. The last one (11) Extech seems a decent choice also and claimed high resolution.

With a Sears unit, if you don't like it, take it back.

[mathog]

Originally Posted by Toasty

Nice sorting... $16.49, $86.83, $49.95...

The site must have been "autoranging". Sears epic tool warranty does not usually apply to their electronic equipment, just to hammers and such. Let's see, what is the warranty on this thing... OK, found it in the user's manual:

ONE YEAR FULL WARRANTY ON CRAFTSMAN AC/DC CLAMP
METER
If this CRAFTSMAN Clamp Meter fails to give complete satisfaction
within one year from the date of purchase, RETURN IT TO THE
NEAREST SEARS STORE OR OTHER CRAFTSMAN OUTLET IN THE
UNITED STATES, and Sears will replace it, free of charge.
This warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.
Sears, Roebuck and Co., Dept. 817WA, Hoffman Estates, IL 60179

The Extech warranty is about the same length, but more restrictive, and
requires a return authorization:

http://www.extech.com/instruments/re...s/MA120_UM.pdf

In the "too many options" department, check out the Mastech catalog

http://www.p-mastech.com/products/cat05.html

Found that when trying to locate the warranty on this one:

http://www.amazon.com/Mastech-Auto-r.../dp/B000BT422W

[Chriso]

Originally Posted by Chriso

I'm just about to buy http://cpc.farnell.com/1/1/34229-cla...226-tenma.html

Because of a current fault I have involving limited access I've changed my mind and ordered a different clamp meter

Range is 0-4A, 0-80A

[Chriso]

Originally Posted by Chriso

Because of a current fault I have involving limited access I've changed my mind and ordered a different clamp meter

Range is 0-4A, 0-80A

Meter arrived - OK so far.

Capacitance check is quick, jaw movement does not affect readings.
I've checked DC current draw on my hard drives and AC on a heater.

I'll check how accurate it is later - I'll mostly be using it for non invasive fault finding in large wiring looms.

Also provides my staff with with a 'non contact' device.

[mathog]

Originally Posted by Chriso

Meter arrived - OK so far.
Capacitance check is quick, jaw movement does not affect readings.
I've checked DC current draw on my hard drives and AC on a heater.

So that low current range must work. What did the drives measure, something around .5-1 A?

If you have an LCD display open please try measuring the AC current on the leads to the tube. That is a much higher frequency than 60 Hz, and it is probably only a few mA, but it would be cool to be able to measure the current draw without having to put a measuring circuit in line with the tube. As tubes age the current draw goes up, so it would be useful to have a way to see "how far along" these are when repairing displays. There is usually enough slack in the two wires that one could get a clamp meter around one.

[Chriso]

Originally Posted by mathog

So that low current range must work. What did the drives measure, something around .5-1 A?

If you have an LCD display open please try measuring the AC current on the leads to the tube. That is a much higher frequency than 60 Hz, and it is probably only a few mA, but it would be cool to be able to measure the current draw without having to put a measuring circuit in line with the tube. As tubes age the current draw goes up, so it would be useful to have a way to see "how far along" these are when repairing displays. There is usually enough slack in the two wires that one could get a clamp meter around one.

Measured draw to a video amp at 110millamps, measurements in my PC were what I expected - checked a 1% 5.7 Ohm resistor which read 5.6.
Had a look around where I've had a .5 Ohm fault - I wish these DC clamps had been invented years ago - apparently they are based on Hall effect devices which were around when I was young - too long ago.

I can't get into an LCD at the moment but probably can get into a similar fluorescent driver - the clamp is ideal for this sort of thing as is fairly small.

For a cheap device it's quite good - it auto ranges and has a 'zero' button for the DC Amp ranges.

My normal clamp meter won't fit in a domestic socket but this will - only problem might be is that the display might not be visible - apparently (the instructions are vague) you can attach a multimeter to the 4mm terminals and read current from there.

Looks like a very useful device.

[mathog]

Originally Posted by Chriso

...ordered a different clamp meter

Who makes that? Is there a model number on it somewhere?

[Chriso]

Originally Posted by mathog

Who makes that? Is there a model number on it somewhere?

Data sheet download

[mathog]

Originally Posted by Chriso

Data sheet download

Thanks. So that's an Extech 380950. Runs around $130 and up on this side of the Atlantic. Not super cheap, but that is probably why it works well.

[Chriso]

Originally Posted by mathog

Thanks. So that's an Extech 380950. Runs around $130 and up on this side of the Atlantic. Not super cheap, but that is probably why it works well.

I paid 50 UK pounds for mine which is a good price as anything quoted in Dollars is usually priced in the UK at a 1 for 1 exchange rate rather than the 'tourists' Dollar/Pound exchange rate.

The cheapest DC Clamp meter I can find is from Tenma - TENMA - 72-7224 - CLAMP METER
Link here

[aayaans]

A high quality dc current clamp ammeter for exact corrosion monitoring will give you timely information for a proactive approach to corrosion management.

[Kiriakos GR]

Hey @aayaans this topic is out of your waters to act as advertizing for your business.

Either way it is time even for you to discover the Brymen BM189 which is the 2013 king, at the range of 150$ retail.