From: no.spam@no.spam.org   
      
   On 2020-03-04 21:40, RobH wrote:   
      
   > The meter I am using is an old Fluke77 digital from RS about 30 or 35   
   > years ago, and I have tried x5 BC547 transistors.   
   > Using the voltage selection, I get 0.0v with negative lead on the   
   > collector and positive on the Emitter, and swapping round I get 0.25v   
   > Using the Ohm selection, I get OL in both directions, and the same using   
   >   the diode selection with the negative lead on the base of the transistor   
   >   
   > I don't have an analogue meter now.   
   >   
   > Thanks   
      
      
   Well, then your transistors look fine as far as you could test them.   
      
   The voltage test is useless, a transistor does not generate a voltage.   
   What you might see is the diode of the B-E (or C-B) rectifying noise   
   from the environment. Useless as an indicator.   
   The ohms range test is also useless, it normally test with 0.2V which is   
   not enough to bias the diode and will give an OL reading in both   
   directions. As you properly described.   
      
   You _MUST_ use the diode testing range!   
   The B-E test should be about 0.55V with + on B side, and OL in the other   
   direction.   
   Same for the B-C test: about 0.55V with + on B side and OL in the other   
   direction.   
   The C-E test should be OL in both directions.   
      
   Regards,   
   Arie   
      
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