DMM Aneng AN860B+

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This is a cheap DMM with all common function.

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It included the DMM, a pair of probes and a manual (Where some specifications was missing).

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The probes has removable tip covers.

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The probes are rated for 10A, I would not trust that but use some more solid wire for 20A range.

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The thermocoupler is a cheap construction rated for max. 400 0.75% 2.5C

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When using the tilting bale the meter is nearly stable enough to turn the switch and push the buttons (If placed on a non-slip surface it will probably be stable enough).

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Meter without rubber sleeve, battery can be replaced without removing this sleeve.

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Display

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The above picture shows all the segments on the display.
Notice how u and m symbols are at multiple locations, making it possible to show them just before the unit.

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Typical display during usage, it will show the number and what measurement is selected.



Functions

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Buttons:
Rotary switch:

Input

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The terminals are a bit loose in the mounting due to the way they are made. My Keysight probes are very loose and cannot be fully pushed down (Standard banana plugs will fit). Opening up the meter and giving the terminals a squeeze may fix it.



Measurements
1uF

A look at the capacity measurement waveform.

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Tear down

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Four screws and the back could be removed.

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6 more screws for the front.

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There is not much inside this meter. The main chip (IC2) is under the black blob, the calibration and function memory is a EEPROM (IC1:24C01). The buzzer (BZZP1) needs a transistor (Q2), same with the backlight (Q1).
There is a long voltage divider chain (R26, R27, R28, R29, R30, R35, R36) of 7 1.5Mohm resistors, this goes directly into the main chip. There is also the test current output (Used in ohm and capacity), this has a PTC (PTC1) and two transistors as clamp (Q3, Q4).
There is a 600mA glass fuse (F2) and two resistors for the uA (R23: 99ohm) and mA (R24: 1ohm) range and 5 diodes (D2, D3, D4, D5, D6) as protection. The 20A ranges has a 10A fuse (F1) and a wire resistor.
Notice the solder blop between tracks just above the battery terminal.

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This side of the circuit board only has the switches and the backlight. The display is connected with a zebra stip.



Conclusion

The meter is easily within the specified tolerances and it has lot of functions and ranges, but the CAT rating is fake.
Glass fuses cannot break high currents at high voltage, it requires ceramic fuses with sand inside. The protection on the ohm/capacity range do not look very robust, i.e. the meter may not survive high voltage on these ranges.
The 6000 count gives a good resolution at 4V and 5V, this can be useful.
Watch out for burden voltage in the 6mA and 600mA range, it can be significant.

I will call it acceptable DMM for hobby use (I am not happy about the bad fit of my other probes), but keep it away from anything with mains voltage and lots of amps.



Notes

This meter exist with many different names on it and small variations in functions.

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