EEVblog #252 – Multimeter Ohms OverloadPosted on March 4th, 2012 4 comments
Is the Agilent meter alone in slow recovery from mains overloading on the ohms range? Let’s find out…
So much videos in a short time !
I love it !
Nice one Dave
Good to know my Fluke87/5 is not going to go bang if I do connect it across mains on ohms range, but dont think I’ll try testing it, just in case
(Though I did do it with a original Fluke 77 once at work, again no problems)
I suppose it can be a pain if you have to wait for it to cool down and come back into spec, but its still better that releasing the magic smoke.
I had to cover my eyes when you plugged the sub-$50 meters into 240 volts, but they did pretty well.
Message to Agilent: If you are going to position a product to compete with the Fluke 87, it should be better in every respect than products costing 1/8 as much.
I like the way my old Fluke 16 handles this test. If you put a stiff voltage source on the meter in Ohms mode, it happily switches to voltage mode, and displays an accurate AC or DC volts, as appropriate. They called this “V-Check”. The owner’s manual even recommends using this technique to eliminate stray “ghost voltage”, because the meter presents a fairly low impedance (2K) to the voltage source in this mode, so only a fairly low-impedance source will read properly.
Pretty neat trick for a relatively basic and inexpensive service technician’s meter.
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