I lost a couple hours to an oddity, thought I'd pass on a heads up.
I have a batch of 2N2222 transistors that were packaged backward. (TO 92) I was setting up a simple switch circuit which was not working correctly. I spent much time double and triple checking my math, as I'm not great at math, but it all checked out. This lead to bumbling and fumbling as well as a bit of fussing. Nothing was making sense. I finally pulled the transistor and put it in my tester, only to find out the package was backward. The emitter and collector were reversed. I put it back in the circuit, in a manner which should have been backward, and everything worked like it was supposed to. China bargains are nice, up until they're not so nice. 😆 They still work like they should when backward. Packages marked. Thought I'd pass it on to possibly save someone else some time....
Thanks for sharing.
This never happened to me, though I had my fair share of fake transistors made in China.
Thanks for the post! I have a bad of 200 2N2222s that I haven't gotten into yet, but will soon for a project to build several boards and to be provided in a kit of parts for those wanting to assemble their own boards, so this is good to know. I'll definitely test each one before including one in those kits!
I tested half of the 100 I have, all were the same, which makes sense. They are produced in batches, then sold in bunches from the batches. If you check a dozen to 20, and they all test the same, its safe to assume they are all the same. (good or bad)
What kind of device would you use to test a transistor?
(◕(' 人 ') ◕)
sorry for the crap pictures.....
Cheap tester from E-Bay, does transistors, capacitors, inductors, and such.