Due special circumstances, the detailed review will follow in few hours, the first wave will be the pictures of the Tear-down. But here is a small introduction, I had send a message to Mastech before two weeks, so to offer to me one of their latest high-tech units for review. The reason that I did that can be explained here. After of two weeks of silence from their side, I lost hope that they will respond. Probably because I discovered even at the 2011 many Chinese brands lacks of innovative products, read here the rest of the story.
Luckily I found one of those V&A Mastech VA18B locally, one close friend of my got one, and what I did was to actually snatch it for a review. The unit is stamped with the logo of a Greek company, that is a known major retailer in Athens. Re-branded by Greek distributor. By looking the pictures of the Tear-down, the first impressions are terrible, there is no need to say that most of my enthusiasm about it had vanish. Even so, I will do several measurements, and I will report my findings in few hours.
V - a unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt; equivalent to the potential difference across a resistance of 1 ohm when 1 ampere of current flows through it. Driver Usb Serial 232, free driver usb serial 232 software downloads.
The manufacturing quality is terrible in my eyes. I do not know who awarded it at 2006, the award logo does not point to the source. But either way I will try to find how bad is it in action, and this is all that I will do. The specific model retails at 40 EUR, equal to the 50$ range. Ok did lots of testing I will just present the numbers so to make your own conclusions.
1) DCV Test On DC the DMM is almost fast and partially accurate and I had spotted a constant error that grows by raising the voltage. Example: Agilent U1272A VS V&A 18B 1.003 --- 1.007 6.000 --- 6022 20.001 --- 20.05 30.000 --- 30.07 33.52 --- 33.60 Reference source 10.002 --- 10.025 The good part it does not overshoot. Display update 2 per second. The DMM are 6000 counts even so at uA it managed to show 6400uA before it gets out of range. I had spotted again a constant error that grows by raising the uA current.
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10uA --- 10uA 100uA --- 100uA 3000uA --- 3007uA 6000uA --- 6018uA Display update 2 per second. 3) The ACV Test I tested it at measuring 220V Mains, it was spot on at 225V with the Agilent next to it. Display update 1 per second. 4) Ohms range. I got very mixed feelings by it. A) The relative functions needs 5-6 seconds to zero out!!
B) From 1-10 ohms the DMM needs four seconds to adjust it self, I had use my resistor decade box, and from the setting of 1 Ohm to two, The DMM needed 4-5 seconds to adjust it self and read 2 Ohms. C) Above the 10 Ohms up to 900K, the DMM needs 1.5 - 3 seconds to read the value, and works a bit faster.
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D) Accuracy acceptable, nothing major here. 5) Capacitance. Probably the most problematic function on it. Examples VS Time in seconds so to read them. 10uF = 5 seconds.