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Old 10th Mar 2016, 8:07 pm   #82
AC/HL
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Join Date: Nov 2003
Location: Idle, Bradford, West Yorkshire, UK.
Posts: 5,410
Default Re: A precision voltage calibrator

I bought one of the cheaper ones, same chip & settings but with jumpers rather than the push button cycling. At first I thought mine was faulty too. Set to 10v it read about 2, gradually creeping up. After a bit of experimentation I found that initially only the 5v setting works, but that once kick started at 5, they all work, and seem accurate (I only have 2.5 digit meters, so can't check to 5 decimal places) Odd. Further checks revealed that left to it's own devices it initially creeps to about 4 than jumps to 10, whereupon all ranges work. But... after setting to 2.5 the slow rise from 2 to 4 starts again. It's reproducible over and over, so must be inherent in the chip (mine at least) They do say to leave it to "warm up" in the instructions.
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