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I just got a Ultrics FBA-0021-YB multimeter and tried to measure some currents. This multimeter has 2 modes of measuring current, one is by connecting the red lead to the 10ADC (10A max) slot, and another by connecting the red lead to the VΩmA (200mA max) slot.

The first method works perfectly but has less digits of precidion so I wanted to use the second method. I tried measuring the current through a LED strip, then a small DC motor, and also a LED backlight. The first method worked always, but with the second would simply almost all of the times not work at all, and give "0.00" with the selector on 10A or "1" on 200ma, 20ma and 2ma.

I read through the manual - it doesn't specify anything in particular about this.

Any help?

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    \$\begingroup\$ probably a blown fuse \$\endgroup\$ – jsotola Mar 18 '20 at 0:10
  • \$\begingroup\$ Is it possible you tried to measure a current above 200mA on that range setting and blew a fuse? Can check if you have another multimeter probe resistance when the setting is on the 200mA range. \$\endgroup\$ – Michael Mar 18 '20 at 0:11
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    \$\begingroup\$ Put in Ω mode and measure to the 200mA input. If the reading is the same as an open circuit, then the fuse is blown. If it reads near zero, then there is something wrong with the meter. \$\endgroup\$ – Aaron Mar 18 '20 at 0:11
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    \$\begingroup\$ Adding to the other comments - it is common for only the low current input socket to be fused and the high-current (10A) in this case to not be fused. Since the low current input is often the voltage measurement input as well it is easy to accidentally apply a voltage source to the low current input and blow the fuse. \$\endgroup\$ – Kevin White Mar 18 '20 at 0:28
  • \$\begingroup\$ Hi, thanks for replies. So i opened the multimeter but i don't think i've found anything that looked like a fuse inside, only a diagonal metal bar coming from the 200ma socket. please check these pictures: ibb.co/CBQSvdW ibb.co/VBwGTW8 ibb.co/BwDqvrr \$\endgroup\$ – Cristian Jorge A. Kusch Mar 18 '20 at 15:16
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It is almost certain that you have a blown fuse on the 200 mA range.
This is extremely easy to do and it is common to find meters wity this fuse blown.

Open the meter. There is almost only this one fuse.
Replace it with one with the same current rating.

If you want to live when you plug the meter into AC mains when it is set to the 200 mA range (as happens) then use an HRC (High rupture capacity) fuse. These usually have a ceramic body. An HRC fuse is rated at say 200 mA (which typically has about a400 mA fast blow rating) fusing current PLUS the ability to break an arc when currents of hundreds of amps start to flow. Residential AC mains is usually capable of supplying a fault current of hundreds of amps. If you plug a fused 200 mA meter circuit into AC mains the very large fault current will blow the fuse in under a milliscond - but an arc may well form across the fuse. An HRC fuse is designed to not support an arc up to current values of hindreds or even thousand of amp. A non-HRC-rated fuse will often allow an arc to form and maintain. Death can happen.

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