Buy Extech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage DetectorExtech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage Detector Product Description:
- Built-in non-contact Voltage detector with LED alert
- 1.5" (40mm) jaw size for conductors up to 500MCM
- 6000 count, backlit LCD display
- Relative Mode for Capacitance Zero and Offset Adjustment
- ata Hold and MIN/MAX, Auto Power Off
Product Description
Extech MA640 True RMS AC/DC Current Clamp Meter with Built-In Non-Contact Voltage Detector
Customer Reviews
Most helpful customer reviews
4 of 4 people found the following review helpful.
Easy one-hand operation, performance matching other Extech meters
By Benedict J. Jackson
The meter is very easy to operate one handed. The function select thumb wheel is much easier to operate than the selector on my Extech EX470. All of the buttons are reachable with your thumb. The focus is on the clamp meter so 4 selector positions are dedicated to the 2 AC and DC clamp amperage ranges. The thermocouple ("temp") setting gets its own position while all of the other functions are packed into two positions on the wheel: One for the ohmmeter, diode tester, capacitance meter and continuity tester, and one for the AC/DC voltmeter and frequency counter/duty cycle. The default modes are ohmmeter and DC volts. The additional functions are cycled with the "mode" button. Although this is a general purpose meter, one of the non-clamp type meters offers quicker access to functions like the cap meter. The non-contact voltage detector is always available in any mode.The max/min feature is handy for making "blind" measurements since the unit will hold the maximum and minimum measured values taken while it is enabled. This allows you to reach into a corner with the clamp meter (or the probes) and take a reading without contorting to see the display. It doesn't work with auto-ranging, though, so be sure to select a range manually first or you may find max says 0L (overflow).The non-contact voltmeter flickers constantly in any mode, becoming solid when the tip of the clamp is near an AC voltage. It is definitely possible to distinguish the random flickering from a solid signal, but the flickering makes it tedious to use to trace wires in walls, where a sharper on/off indication would be helpful.The ohmmeter and voltmeter have the same slow, confusing auto-ranging as my Extech EX470. While it searches for a range the display will show intermediate values and only the stabilization of the result lets you know it is done.The continuity meter has changed since the EX470. The 470 beeper was just tied directly to the probes, making noise for exactly as long as they were in contact, leading to a screechy sound. The MA640 now has a minimum beep time, but also a minimum continuity time before the beep starts. Compare that to my favorite continuity meter, the Fluke 10, which has a minimum beep time for any contact. You can drag the probes of the Fluke across many pins and rely on hearing a clear beep if you brush anything connected to the other probe. The MA640 is more pleasant sounding than the EX470 but possibly even less useful. You can literally strike the probes against each other without a sound.The clamp meter seems accurate but I have only employed it at fairly low amperages and mostly on DC. Be sure to hit "REL" to zero out the DC measurement before starting.The included probes are the same as other Extech meters I've seen. The quality is good but not great. There are protective caps and room to store them in the included case. The thermocouple is a type-K with a bead (rather than a pointy probe). The blue tube securing the end of the thermocouple insulation did not survive a 300C environment I measured.The backlight is white and plenty bright. There is no stand and the back of the meter is rounded. That makes it comfortable to hold but difficult to prop up. Maybe you can hang it by the clamp when using it on a desk.
0 of 0 people found the following review helpful.
Nice clamp meter
By srs06
I've spent years getting by with only probe meters but kept finding a need for a clamp meter. I was looking for a true RMS meter and settled on this one. I've used it many times since buying it and it works very well. Not much to add regarding the details that other reviewers haven't already covered. For measuring current of household devices, make sure you get an Extech 480172 AC Line Splitter or similar device. Extech products have been good for me.
1 of 3 people found the following review helpful.works good
By dimi
Amazon send me 2 by mistake (charging me for 2) on one of wich the noncontact curent detector wasn't working. But I was going to return one of them aniway! Got delivered fast as usual!
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