Help with Transistor testing

[Jake_Rezac]

Ive been trying to make some simple circuits at home and have been harvesting transistors from old appliances to do so. Ive looked up tutorials on how to test these transistors and found that a measure of resistance should be returned on a multimeter when the positive probe is on the base and negative probe is on either of the other leads of an NPN transistor. However, all of the measurements only return a resistance reading when the negative probe is on one of the leads. I cant even find which pin is the emmitter and which is the collector on the data sheet. This has been happening with the utc tl431 transistor. Is this transistor still good? what am I doing wrong?

 

[BobK]

Does you multimeter have a diode setting?

Bob

 

[Arouse1973]

Hello Jake
The TL431 is a shunt regulator not a transistor
Thanks
Adam

 

[(*steve*)]

Jake, it's always a good idea to google for the part number that appears on a salvaged device such as this.

In this case you would have discovered datasheets, circuits, etc showing you all you need to know. Of course you may not understand it all, but we could help you with that