It depends on your particular multimeter, different types output different polarities - it's best to test a known transistor, to see which way round it works. Essentially a transistor tests as two diodes, with the base common, so it should read from both base to emitter, and base to collector, one way round - and not at all the other.
Some multimeters have a transistor check socket, it may be useful to you.
I agree with what Nigel wrote above or you can read this information on transistor http://www.geocities.com/bagtool/trans_check.html
In addition, remember that the diode from collector to base has less junction voltages than the emitter to base diode, should u use diode tester that gives junction voltages (knee voltages) as well. This is because emitter is heavily biased as compared to the collector.
In addition, remember that the diode from collector to base has less junction voltages than the emitter to base diode, should u use diode tester that gives junction voltages (knee voltages) as well. This is because emitter is heavily biased as compared to the collector.
In addition, remember that the diode from collector to base has less junction voltages than the emitter to base diode, should u use diode tester that gives junction voltages (knee voltages) as well. This is because emitter is heavily biased as compared to the collector.
Yes, it's a pretty comon practice when one doesn't know the transistor type. Interesting to see that you didn't know this :wink: (considering your many years of experience, no offense).
Presumably it's the 'youngsters' brought up on digital meters that know about this?, us 'oldies' brought up on analogue meters don't know about it, because it wasn't possible to measure!.
Yes, there's a small company not too far from me that manufactures them (amongst other test equipment), and they are built around PIC's :lol: https://www.peakelec.co.uk
Just had a quick measure, it's about 22 miles away, as the crow flys!.
When you don't know yet which one is emitter and which one colector, you put your multimeter between them to measure resistance.
Then with your finger more or less humid (wet?), you alternatively shortcircuit each one with the base. When you see a change in the measurement, you have identified the collector.
Obviously, polarity between emitter and collector should allow this.
Long time I don't do this but used it many times in the past.
If I recall properly, didn't work with power transistors...