good inexpensive DC clamp ammeter?

[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