I found what I thought was the perfect part for a current mirror. Datasheet here:
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But then I saw the spec on page three for matching of the collector currents, the datasheet says it can vary from .7 to 1.3. Is this for real? I dug out a tape of pn2222a transistors and checked a bunch of the transistors on the tape at random, and the max error was way short of ten percent. You'd think a dedicated current mirror would work at least as good, by design. Maybe they're just being super-conservative on the datasheet, but it puts me off buying the part. I have to go by the numbers they publish.